#include<cstdio>
#include<iostream>
#include<queue>
using namespace std;
int read()
{
	int x,f=1;
	char ch;
	while(ch=getchar(),!isdigit(ch))if(ch=='-')f=-1;
	x=ch-48;
	while(ch=getchar(),isdigit(ch))x=x*10+ch-48;
	return x*f;
}
void write(int x)
{
    if(x<0)putchar('-'),x=-x;
	int cnt=0;char ch[30];
	while(ch[++cnt]=x%10+48,x/=10);
	while(putchar(ch[cnt]),--cnt);
	putchar('\n');
}
int f[1050];
int main()
{
	freopen("translate.in","r",stdin);
	freopen("translate.out","w",stdout);
	int m=read(),n=read();
	int cnt=0,ans=0;
	queue<int> q;
	for(int i=1;i<=n;i++)
	{
		int x=read();
		if(f[x])continue;
		f[x]=1;
		ans++;
		if(cnt<m)
		{
			cnt++;
			q.push(x);
		}
		else if(cnt==m)
		{
			f[q.front()]=0;
			q.pop();
			q.push(x);
		}
	}
	write(ans);
}