#include <iostream>
using namespace std;
 
namespace MathTools {
    double PI = 3.14159;
    
    double circleArea(double radius) {
        return PI * radius * radius;
    }
}
 
namespace StringTools {
    string repeat(string text, int times) {
        string result = "";
        for (int i = 0; i < times; i++) {
            result += text;
        }
        return result;
    }
}
 
int main() {
    cout << MathTools::circleArea(5) << endl;
    cout << StringTools::repeat("Ha", 3) << endl;
    return 0;
}