//
// Created by 南川 on 2021/2/13.
//
#include "cstdio"
const int M = 100 + 1, N = 1000 + 1;
int m, n, ni, ans, qi, qj, que[N], isIn[N];
int main()
{
// freopen("/Users/mark/MarkLearningCPP/Acwing/496. 机器翻译/case2.txt", "r", stdin);
scanf("%d %d", &m, &n);
for(int i=1; i<=n; ++i)
{
scanf("%d", &ni);
if(isIn[ni]) continue;
++isIn[ni];
que[++qj] = ni;
++ans;
if(qj - qi > m)
--isIn[que[++qi]];
}
printf("%d", ans);
}