#include <iostream>
#include <math.h>
using namespace std;
int main()
{
    int n,S_f;
    cout<<"n=";
    cin>>n;
    if(n%10==1)
        S_f=n/10*7+1;
    else if(n%10==2)
        S_f=n/10*7+5;
    else if(n%10==3)
        S_f=n/10*7+2;
    else if(n%10==4)
        S_f=n/10*7+8;
    else if(n%10==5)
        S_f=n/10*7+3;
    else if(n%10==6)
        S_f=n/10*7+9;
    else if(n%10==7)
        S_f=n/10*7+2;
    else if(n%10==8)
        S_f=n/10*7+8;
    else if(n%10==9)
        S_f=n/10*7+7;
    cout<<S_f%10;
}