#include<fstream>
using namespace std;
ifstream f("cifra.in");
ofstream g("cifra.out");
int r,n,c,t;
int main()
{f>>n;
r=n%20;
c=n/20;
if(r==0)
	t=0;
else
	if(r==1||r==17)
		t=1;
	else
		if(r==3||r==70)
			t=2;
		else
			if(r==5||r==14)
				t=3;
			else
				if(r==12||r==16||r==19)
					t=4;
				else
					if(r==2||r==18)
						t=5;
					else
						if(r==9||r==10||r==13)
							t=7;
						else
							if(r==4||r==8||r==11||r==15)
								t=8;
							else
								if(r==6)
									t=9;
c=c*4+t;
c=c%10;
g<<c;
return 0;
}