#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main()
{
    int r,a1,a2,d;
    const float p=22/7;
    scanf("%d",&r);
    if(r>=1 && r<=100)
    {
    a1=p*r*r;
    a2=p*1*1;
    d=a1/a2;
    printf("%d",d);
    }
    else
        printf("out of the range");

        return 0;
}
