#include<bits/stdc++.h>
using namespace std;
#define rep(i,x,y) for(int i=x;i<y;i++)
#define range(a) (a).begin(),(a).end()
#define print(A,n) rep(i,0,n){cout<<(i ? " ":"")<<A[i];}cout<<endl;
#define pprint(A,m,n) rep(j,0,m){print(A[j],n);}
const int mod=1e5;
const int size=1e5;
const long inf=1e9;
int main(){
	int N;cin>>N;
	if(N==0){ cout<<0<<endl; return 0; }
	long res=1;long a;
	rep(i,0,N){
		cin>>a;
		if(a==0){ cout<<0<<endl; return 0; }
		(res*=(a%9))%=9;
	}
	cout<<(res==0 ? 9 : res)<<endl;
}