// your name, program description
#include <iostream>

using namespace std;

double y;       // a global variable

double g(double x){ return x*x - y; } // function definition

int main()
{
    double x;
    cout << "Enter x: ";
    cin >> x;
    cout << "Enter y: ";
    cin >> y;
    double z = g(x);
    cout << "g(x) = " << z << 'n';
    return 0;
}