#include <iostream>
#include <fstream>
#include <math.h>
using namespace std;
ifstream f("cifra.in");
ofstream g("cifra.out");
int n,i,S,c;
int main()
{
    f>>n;
    for (i=1; i<=n; i++)
        S=pow(i,i);
    c=S%10;
    g<<c;
}