#include <iostream>
#include <fstream>
using namespace std;

int main()
{int T,N,S,c;
    S=0;
    fstream f("fact.in",ios::in);
    f>>T;
    for(N=1;N<=T;N++)
    S=S+N*N;
c=S&10;
fstream g("fact.out",ios::out);
g<<c;
    return 0;
}