#include<bits/stdc++.h>
using namespace std;
using Int = long long;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}

//INSERT ABOVE HERE
signed main(){
  Int n;
  cin>>n;
  Int ans=1,flg=0;
  for(Int i=0;i<n;i++){
    Int p;
    cin>>p;
    flg|=p==0;
    ans*=p;
    ans%=9;
  }
  if(!flg&&ans==0) ans=9;
  cout<<ans<<endl;
  return 0;
}