#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
    ll n, k;
    cin>>n>>k;
    vector<ll> v(k);
    set<ll> s;
    for (int i = 0; i < k; i++) {
        ll a; cin>>a;
        v[i] = a;
        s.insert(a);
    }
    int ans = 0;
    for (ll x : v) {
        int cnt = 0;
        if (s.empty()) break;
        if (x < *s.begin()) continue;
        while (*s.begin() < x) {
            s.erase(s.begin());
            cnt++;
        }
        s.erase(s.begin());
        if (cnt) ans++;
    }
    cout << ans << '\n';
}