#include <fstream>
#include <iostream>
#include <stdio.h>
using namespace std;
int main()
{ ifstream fi("cifra.in");
  ofstream fo("cifra.out");
  int t,i,n,k,a;
  n=0;
  fi >> t;
  k=1;
while (k<=t)
{ a=1;
      for (i=0;i<k;i++)
       a = a*k;
          n = n + a;
    fo << n%10;
  k++;
} 
fi.close();
fo.close();
system("pause");
return 0;

}