#include <bits/stdc++.h>
using namespace std;
int n,  m, c, c1;
bool a[100001];
queue<int> b;

int main() {
	cin >> m >> n;
	for (int i = 1; i <= n; i++) {
		cin >> c;
		a[i] = c;
		if (a[c] != 1) {
			continue;
		} else {
			if (b.size() >= m) {
				a[b.front()] = 0;
				b.pop();
			}
			b.push(c);
			a[c] = 1;
			c1++;
		}
	}
	cout << c1;
	return 0;
}