#include <stdio.h>
 #include <math.h>
int main(){  
         double a,d;
         int c;
          double b=1;
          double e=0;
          double i=0;
 FILE *f=fopen("cifra.in","r"),*g=fopen("cifra.out", "w");
 fscanf(f,"%d",&a);  
 while (i<a){
               d=pow(b,b);
               c=d+e;
               e=c;
               b=b+1;
               i=i+1;
}
c=c%10;
fprintf (g,"%d \n",c);
return 0;
}