#include <iostream>
#include <cmath>

int main() {
    double x = 15.8;
    double y = 5.4;
    double result = fdim(x, y);

    if (result == 0) {
        std::cout << "The positive difference is zero." << std::endl;
    } else {
        std::cout << "Positive difference between " << x << " and " << y << " is: " << result << std::endl;
    }

    return 0;
}