#include<bits/stdc++.h>
using namespace std;

int main(){
	cin.tie(0),ios::sync_with_stdio(false);
	int n; cin>>n;
	int64_t ans=1;
	for(int i=0;i<n;++i){
		int64_t p; cin>>p;
		if(p==0){
			cout<<0<<"\n"s;
			return 0;
		}
		ans*=p%9;
		ans%=9;
	}
	cout<<(ans==0?9:ans)<<"\n"s;
}