#include <iostream>
using namespace std;

float Circum(float val);
int main(){
    float radius;

    cout<<"Enter the Radius of the Circle: ";
    cin>>radius;
    cout<<"The Area of the Circle: "<<Circum(radius);

    return 0;
}

float Circum(float val){
    float ans;
    float pi=3.14;

    ans=2*pi*val;
    return ans;
}