#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<cmath>
#include<queue>
using namespace std;

bool a[1010];
int main() {

	queue<int> q;
	int ans = 0;
	int m, n;
	int nn;
	cin >> m >> n;
	for (int i = 1; i <= n; i++) {
		cin >> nn;
		if (a[nn]) {
			continue;
		}
		if (q.size() < m) {
			q.push(nn);
			a[nn] = true;
			ans++;
		}
		if (q.size() >= m) {
			a[q.front()] = false;
			q.pop();
		}
	}
	cout << ans << endl;

	return 0;
}