#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 int64_t ll;

bool ins(ll i, ll j, ll n, ll m) {
    if(i < 0 || j < 0 || i >= n || j >= m) {
        return false;
    }
    return true;
}

void solve() {

    ll n, m;
    cin >> n >> m;
    
    set<pair<ll, pair<ll,ll>>> s;

    vector<vector<ll>> v(n, vector<ll>(m, 0));
    for(ll i = 0; i < n; i++) {
        for(ll j = 0; j < m; j++) {
            cin >> v[i][j];
            if(v[i][j] != 0) {
                s.insert({v[i][j], {i, j}});
            }
        }
    }
    
    vector<pair<ll,ll>> ans;

    const vector<pair<ll,ll>> dir = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};

    vector<vector<bool>> vis(n, vector<bool>(m, false));
    while(!s.empty()) {

        auto c = *s.begin();
        s.erase(s.begin());

        ll cw = c.first;
        ll i = c.second.first;
        ll j = c.second.second;

        if(vis[i][j] == false) {
            vis[i][j] = true;
            ans.push_back({i, j});
        }

        for(const auto & [hi, hj] : dir) {
            ll ci = i + hi;
            ll cj = j + hj;

            if(ins(ci, cj, n, m) && vis[ci][cj] == false && v[ci][cj] >= v[i][j]) {
                vis[ci][cj] = true;
                s.erase({v[ci][cj], {ci, cj}});
                s.insert({0, {ci, cj}});
            }
        }
    }
    
    cout << ans.size() << "\n";
    for(const auto & [i, j] : ans) {
        cout << i+1 << " " << j+1 << "\n";
    }

}

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

    solve();

    return 0;
}