#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod = 1000000007;
const ll inf = 3e18;
const char sp = ' ';


int N, A;
set<int>st;
int main() {
	cin >> N;
	while (N--) {
		cin >> A;
		st.insert(A);
	}
	cout << st.size() << endl;
}
