#include <iostream>
#include <vector>
#include <bitset>

using namespace std;

const int N = 1010;

int get_unique_count(vector<int> a, int n){
    int res = 0;
    bitset<N> cnt;
    for(int i = 0;i < n;++i){
        cnt.set(a[i]);
    }
    res = cnt.count();
    return res;
}

int main(){
    int n;
    cin >> n;
    vector<int> a(n);
    for(int i = 0;i < n;++i)cin >> a[i];
    cout << get_unique_count(a,n) << endl;
    return 0;
}