#include<fstream>
#include<string>
using namespace std;
int x[][2]={
  {0,0},{1,1},{5,7},{8,4},{4,0},{9,5},{5,1},{8,8},{4,2},{3,1}
};
int main(){
  char N[105];
  ifstream f("cifra.in");
  f>>N;
  f.close();
  int m, bit, r, cifra;
  int length=strlen(N);
  m=(int)N[length-1];
  N[length-1]=0;
  length--;
  bit=(int)N[length-1];
  bit=bit&1;
  r=(int)N[length-1];
  r=r>>1;
  cifra=4*r+3*bit+x[m][bit];
  ofstream g("cifra.out");  
  g<<(cifra%10);
  g.close();
  return 0;
}