#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    int N; cin >> N;
    vector<ll> P(N);
    rep(i,N) cin >> P[i];
    int ZERO = 0;
    rep(i,N) ZERO |= P[i] == 0;
    if(ZERO) {
        cout << 0 << endl;
    } else {
        ll ans = 1;
        rep(i,N) ans = (ans * (P[i] % 9)) % 9;
        cout << (ans == 0 ? 9 : ans) << endl;
    }
}