#include<iostream>
#include<stack>
#include<queue>
int m,n,t,haid,tail,ans;
queue<int> q;
bool f[1010];
using namespace std;
int main(){
	cin>>m>>n;
	for(int i=1;i<=n;i++){
		cin>>t;
		if(f[t])
			continue;
		f[t]=1;
		ans++;
		if(q.size()>=m){
			f[q.front()]=0;
			q.pop();
		}
		q.push(t);
	}
	cout<<ans;
	return 0;
}