#include <iostream>
#include <vector>
#include <cmath>
#include <string>
#include <cstdio>
#include <algorithm>
#include <map>
#include <queue>
#include <cstdlib>
#include <cstdio>
using namespace std;

#define next '\n'
#define rep(i, n) for(int (i) = (0); (i) < (n); (i++))
using ll = long long;
using ull = unsigned long long;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n; cin >> n;
    int ans = 1;
    rep(i, n){
        int p; cin >> p;

        p = p % 9;
        ans *= p;
        ans = ans % 9;
    }

    if(ans == 0){
        cout << 9;
    }else{
        cout << ans;
    }

    cout << next;
}