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

typedef long long ll;

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