#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <stack>
#include <algorithm>
#include <string>
#include <map>
#include <iterator>
#include <set>
#include <queue>
#include <bitset>
#include <cassert>

using namespace std;

int main() {

    int N;
    cin>>N;
    set<int>s;
    for (int i = 0; i < N; ++i) {
        int A;
        cin>>A;
        s.insert(A);
    }
    cout << s.size()<<endl;
}