#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
typedef long long ll;
typedef pair<int,int> pp;
const int INF = 1e9;
const int MOD = 1000000007;


int main() {
    int n;
    cin >> n;
    vector<ll> a(n);
    rep(i,n) cin >> a[i];
    sort(a.begin(),a.end());
    if(a[0] == 0){
        cout << 0 << endl;
        return 0;
    }
    int ans = 1;
    rep(i,n){
        a[i] %= 9;
        ans *= a[i];
        ans %= 9;
    }
    if(ans ==0) cout << 9 << endl;
    else cout << ans << endl;
    

    return 0;  
}