#include <iostream>
#include <algorithm>
using namespace std;
const int N(1009);
int sto[N]={0},s[N]={0};
bool exist[N]={0};
int main()
{
    int m,n,ans(0),word;
    cin>>m>>n;
    for(int i=1,p=1;i<=n;i++)
    {
        scanf("%d",&word);
        if(!exist[word])
        {
            ans++;
            exist[word]=true;
            if(sto[0]<m)
            {
                sto[0]++;
                sto[sto[0]]=word;
            }
            else
            {
                exist[sto[p]]=false;
                sto[p]=word;
                p++;
                if(p>m)
                    p=1;
            }
        }
    }
    cout<<ans<<endl;
    return 0;
}

/**************************************************************
	Problem: 2296
	User: admin
	Language: C++
	Result: Accepted
	Time:48 ms
	Memory:2080 kb
****************************************************************/