#include <iostream>
#include <fstream>
#include <math.h>
using namespace std;

int main()
{


    ifstream f("cifra.in");
    ofstream g("cifra.out");
    int n,s,i,nr,u;

    f>>n;
    for(i=1;i<=n;i++){
                     f>>nr;

                                       u=i%10;

                                       s=(s+int(pow(u,u)))%10;

                                       }

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