#include <iostream>
using namespace std;
int get_unique_count(int a[], int n)
{
for (int i = 0; i < n; i ++ )
for (int j = i + 1; j < n; j ++ )
if (a[i] == a[j]) a[j] = 0;
int s = 0;
for (int i = 0; i < n; i ++ )
if (a[i] != 0) s ++ ;
return s;
}
int main()
{
int a[1010];
int n;
cin >> n;
for (int i = 0; i < n; i ++ ) cin >> a[i];
cout << get_unique_count(a, n) << endl;
return 0;
}