#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;

using ll = long long int;

int main() {
    ll n, ans = 1;
    bool zr = false;
    cin >> n;
    for(int i=0;i<n;i++){
        ll a;
        cin >> a;
        if(a == 0) zr = true;
        ans *= a;
        ans %= 9;
    }
    if(ans == 0 && !zr) ans = 9;
    cout << ans << endl;
    return 0;
}