#include <iostream>
#include <fstream>
#include <cstring>

using namespace std;

int main()
{
    ifstream in ("cifra.in");
    ofstream out ("cifra.out");
    int n,p;
    int r[4][10]={0,1,6,1,6,5,6,1,6,1,
                  0,1,2,3,4,5,6,7,8,9,
                  0,1,4,9,6,5,6,9,4,1,
                  0,1,8,7,4,5,6,3,2,9};
    char nr[102];
    ///n la puterea p
    ///este acelasi cu (ultima cifra a lui n) la p
    ///este acelasi cu (ultima cifra a lui n) la (p%4)
    ///(n%10) la (p%4)

    //for(int i=0;i<=3;i++)
    //    for (int j=1;j<=9;j++) cout<<r[i][j]<<" ";
    //cin>>n;
    in>>nr;
    p=strlen(nr);
    n=(nr[p-3]-48)*100+(nr[p-2]-48)*10+(nr[p-1]-48);
    int s=(n/40)%10*8;
    for (int i=1;i<=n%40;i++){
        s=s+r[i%4][i%10];
    }
    out<<s%10;

    return 0;
}