#include<iostream>
#include<cstdio>
using namespace std;
bool pd[1001];
int a[1001];
int main() {
	int m,n,i,x,head=1,tail=1,ans=0;
	cin>>m>>n;
	for(i=1; i<=n; i++) {
		cin>>x;
		if(pd[x]==1)
			continue;
		else {
			if((tail-head+1+m)%(m)==m) {
				pd[a[head++]]=0;
			}
			if(tail==m)
				tail=1;
			a[x]=1;
			a[++tail]=x;
			ans++; 
		}
	}
	cout<<ans;
	return 0;
}