#include <iostream.h>
#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;
}