文件目录

#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
    double r;
    cin >> r;
    double pai = 3.1415926;
    cout << fixed << setprecision(4) << 2 * r;
    cout << " ";
    cout << fixed << setprecision(4) << 2 * pai * r;
    cout << " ";
    cout << fixed << setprecision(4) << pai * r * r;
    return 0;
}