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

e=e%10;
a=e;
fprintf (g,"%d \n",a);
return 0;
}