#include <iostream.h>
#include <fstream.h>
fstream f("cifra.in",ios::in);
fstream g("cifra.out",ios::out);
int main ()
{
 long n,p,c,i,d,s;
 f>>n;
 s=0;
 for (i=1;i<=n;i++) {
		     p=1;
		     d=i;
		     while (d>0) {
				   p=p*i;
				   d=d-1;
				   }
		     s=s+p;
		     c=s%10;
		     g<<c;
		     }
 f.close ();
 g.close ();
 return 0;
}