骗走AC

#include <bits/stdc++.h>
using namespace std;
int main(){
    double a;
    cin >> a;
    printf("%.4f",a*2);
    cout << " ";
    printf("%.4f",2*3.14159*a);
    cout << " ";
    printf("%.4f",3.14159*pow(a,2));
    cout << " ";
    return 0;
}