#include<cstdio>
const int N=30010;
int n,cnt[N];
int main()
{
freopen("stolen_necklace.in","r",stdin);
freopen("stolen_necklace.out","w",stdout);
scanf("%d",&n);
for (int i=1;i<=n;i++){
int x;
scanf("%d",&x);
cnt[x]++;
}
int ans=0;
for (int i=0;i<N;i++) if (cnt[i]) ans++;
printf("%d\n",ans);
return 0;
}