#include <bits/stdc++.h>

using namespace std;

int n, m, num = 0, ans = 0;
//利用数组桶排
bool path[1001] = {0};
queue<int> Q;

int main() {
    cin >> m >> n;
    for (int i = 1; i <= n; i++) {
        int x;
        cin >> x;
        if (!path[x]) {
            num++;
            ans++;
            Q.push(x);
            path[x] = 1;
            if (num > m) {
                path[Q.front()] = 0;
                Q.pop();
                num--;
            }
        }
    }
    cout << ans << endl;
    return 0;
}