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

using namespace std;

int main()
{
    ifstream input ("cifra.in");
    long long int v[30000];
    int i = 0;
    while(!input.eof()){
        input >> v[i];
        i++;
    }
    i -= 2;
    input.close();
    ofstream output ("cifra.out");
    int ct;
    for(ct = 0;ct <= i;ct++){
        long long int sum = 0;
        for(int start = 1; start <= v[ct]; start++){
            sum = sum + pow(start, start);

        }
        output << sum % 10 << endl;
    }
    output.close();
    return 0;
}