#include <fstream>

using namespace std;
int N,i,j,s,T;
int main()
{
    ifstream fin ("cifra.in");
    fin>>T;
    fin>>N;

    ofstream fout ("cifra.out");
    s=0;
    for (N=1;N<=T;N++)
    {
        for (j=1;j<=N;j++)
        {
            j=j*j;
        }
        s=s+j;
        fout<<s%10;
    }

    fin.close ();
    fout.close ();
    return 0;
}