#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <time.h>
#include <stack>
#include <array>
#define popcount __builtin_popcount
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;

int main()
{
	int n;
	cin>>n;
	ll p[100010];
	ll x=1;
	for(int i=0; i<n; i++){
		cin>>p[i];
		if(p[i]==0){
			cout<<0<<endl;
			return 0;
		}
		p[i]%=9;
		x=x*p[i]%9;
	}
	if(x==0) cout<<9<<endl;
	else cout<<x<<endl;
	return 0;
}