#include <iostream>
#include <fstream>
#include <math.h>

using namespace std;

int main()
{
        ifstream f("cifra.in");
        ofstream g("cifra.out");

    int t,i ;
    f >> t ;
    long long v[t+1] ;
    for (i=1;i<=t;i++) {f >> v[i] ;v[i]=v[i]%10;}

     long long suma = 0 ;

      for (i=1;i<=t;i++)

      {
          suma += pow(v[i],v[i]);
          suma = suma % 10 ;
      }

g<<suma;
    f.close();
    g.close();
    return 0;
}