#include <iostream>
#include <algorithm> // for sort, mainly
#include <vector>
#include <map>
#include <set>
#include <cmath>
#include <array>
#include <string>
#include <cstdio>
#include <iterator>
#include <unordered_set>
#include <cstdint> // for int64_t, int32_t, etc
#include <queue>
#include <stack>
#include <deque>
#include <numeric> // gcd, lcm
#include <fstream>
#include <bitset> // for bitset
#include <iomanip>
#include <cassert> // for set with custom ordering
#include <type_traits> // for set with custom ordering
#include <utility> // for swap, forward, etc
using namespace std;

#pragma GCC optimize("O2")
// #pragma GCC optimize("O1","O2","O3","Ofast","unroll-loops")
//#pragma GCC target("sse","sse2","sse3","sse4.1","sse4.2","avx","avx2","fma")

template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ", " << p.second << ')'; }
template<typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type> ostream& operator<<(ostream &os, const T_container &v) { os << '{'; string sep; for (const T &x : v) os << sep << x, sep = ", "; return os << '}'; }
void dbg_out() { cout << endl; }
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cout << ' ' << H; dbg_out(T...); }
#ifdef LOCAL
#define dbg(...) cout << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__)
#else
#define dbg(...)
#endif

/*
 *
 * notes:
 *
 * int64_t
 * stoi(string s) -> string to int
 * to_string() -> int (or else) to string
 *
 * vector declaration:
 * vector<ll> v(n, 0)
 * vector<vector<ll>> v(n, vector<ll>(n, 0));
 *
 * {if statement} ? {truth value} : {false value}
 *
 * set lower bound/upper bound:
 * 	// . . . m1 . . . d . . . . m2
 *    auto m1_it = b.lower_bound(d);
 *    advance(m1_it, -1);
 *    m1 = *m1_it;
 *	m2 = *b.upper_bound(d);
 *
 * #ifdef LOCAL
 *    freopen("in.txt","r",stdin);
 *    freopen("out.txt","w",stdout);
 * #endif
 *
 * constexpr auto lcm(auto x, auto... xs)
 * {
 *	return ((x = std::lcm(x, xs)), ...);
 * }
 *
 * std::gcd(int a, int b)
 *
 * cout << setprecision(n);
 *
 * set with custom ordering
 * set<ll, decltype(&cmp)> qu(cmp);
 *
 */

typedef int32_t ll;

// range query
class sqrtdecomp{

    // range query, range question
    // increase value in range [a, b]
    // maximum value in range [a, b]?

    private:
        ll n;
        ll sq;
        vector<ll> v;
        vector<ll> gi; // global increase
        vector<ll> s;

        void updatesegment(ll seg) {

            s[seg] = 0;

            for(ll i = seg * sq; i < min((seg + 1) * sq, n); i++) {
                v[i] += gi[seg];
                s[seg] = max(s[seg], v[i]);
            }

            gi[seg] = 0;
        }

    public:

        void init(ll size, vector<ll> input) {

            n = size;
            sq = sqrtl(n);
            if(sq * sq < n) {
                sq++;
            }

            v.resize(n, 0);
            gi.resize(sq, 0);
            s.resize(sq, 0);
            ll j = 1;
            for(ll i = 0; i < n; i++) {
                v[i] = input[i];
            }

            for(ll i = 0; i < sq; i++) {

                ll mx = 0;

                for(ll k = i * sq; k < min((i+1) * sq, n); k++) {
                    mx = max(mx, v[k]);
                }

                s[i] = mx;
            }
        }

        void debug() {

            cerr << "\nn=" << n << "; sq=" << sq;
            cerr << "\nv=" << v;
            cerr << "\ngi=" << gi;
            cerr << "\ns=" << s;
        }

        void update(ll a, ll b, ll x) {

            ll segl = a / sq;
            ll segr = b / sq;
            
            //cerr << "\nsegl=" << segl;
            //cerr << "\nsegr=" << segr;
            
            if(segl == segr) {
                // manually update
                for(ll i = a; i <= b; i++) {
                    v[i] += x;
                }

                updatesegment(segl);
            }
            else{

                // update until next segment
                for(ll i = a; i < (segl+1) * sq; i++) {
                    v[i] += x;
                }
                updatesegment(segl);

                for(ll i = segl+1; i <= segr - 1; i++) {
                    gi[i] += x;
                }

                for(ll i = segr * sq; i <= b; i++) {
                    v[i] += x;
                }
                updatesegment(segr);
            }
        }

        ll query(ll a, ll b) {
            // max from range a, b
            
            ll segl = a / sq;
            ll segr = b / sq;

            ll ret = 0;

            if(segl == segr) {
                updatesegment(segl);
                for(ll i = a; i <= b; i++) {
                    ret = max(ret, v[i]);
                }
            }else{

                // update until next segment
                updatesegment(segl);
                for(ll i = a; i < (segl+1) * sq; i++) {
                    ret = max(ret, v[i]);
                }

                for(ll i = segl+1; i <= segr - 1; i++) {
                    ret = max(s[i] + gi[i], ret);
                }

                updatesegment(segr);
                for(ll i = segr * sq; i < min(n, (segr+1) * sq); i++) {
                    ret = max(ret, v[i]);
                }

            }

            return ret;
        }
};

void check(){

    ll n = 10;
    vector<ll> v(n, 1);
    sqrtdecomp sq;
    sq.init(n, v);
    sq.debug();

    sq.update(0, 9, 2);
    sq.debug();
    sq.update(4, 5, -1);
    sq.debug();

}

void solve() {

    ll n, m;
    cin >> n >> m;

    ll lim = pow(2, n);
    vector<ll> v(lim, 1); // distance from node to parent

    vector<ll> inp(lim, n-1);
    sqrtdecomp sq;
    sq.init(lim, inp);     

    ll downleft = lim / 2;
    ll downright = lim - 1;

    //cerr << "\ndownleft=" << downleft << "; downright=" << downright;

    for(ll i = 0; i < m; i++) {
        ll node, len;
        cin >> node >> len;

        ll diff = len - v[node];
        v[node] = len;

        //cerr << "\ndiff=" << diff;
        
        // megnezzuk melyik a legbalso, illetve legjobbso leszarmazottja
        ll left = node;
        while(left * 2 < lim) {
            left *= 2;
        }
        ll right = node;
        while((right) * 2 + 1 < lim) {
            right = (right) * 2 + 1;
        }
        //cerr << "\nleft=" << left << "; right=" << right;
        sq.update(left, right, diff);

        //sq.debug();

        cout << sq.query(downleft, downright) << "\n";

    }

}

int main()
{
    //check();
    //return 0;

    std::ios_base::sync_with_stdio(false);
    //cin.tie(nullptr);
    //cout.tie(nullptr);

    solve();

    return 0;
}