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

#define int long long
#define double long double

#define pii pair<int, int>

signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
#ifdef CB
	freopen("be2.txt", "r", stdin);
//	freopen("out.txt", "w", stdout);
#endif
	int N, K;
	cin >> N >> K;
	vector<int> v(K);
	set<int> s;
	for (int i = 0; i < K; i++) {
		cin >> v[i];
		s.insert(v[i]);
	}
	int ans = 0;
	for (int i = 0; i < K; i++) {
		if (!s.erase(v[i])) {
			continue;
		}
		if (s.lower_bound(v[i]) != s.begin()) {
			ans++;
		}
		s.erase(s.begin(), s.lower_bound(v[i]));
	}
	cout << ans << '\n';
	return 0;
}