Contest1388/E.cpp

#include <bit/stdc++.h>

using namespace std;
const double PI = atan(1.0) * 4;

int main() {
    int n;
    double r;
    for (cin >> n; cin >> r, n--;) {
        cout << fixed << setprecision(6) << PI * r * r << endl;
    }
    return 0;
}