#include <iostream>
#include <stdio.h>
#include <stdlib.h>
using namespace std;

int main()
{
    int r,result;
    double area,area2;
    float pi=3.14159;
    cin>>r;
    area=pi*r*r;
    area2=pi;
    result=area/area2;
    printf("%d",result);
    return 0;
}
