using namespace std;

#include <iostream>

int Greatest_Common_Divisor (int j, int k);

int Greatest_Common_Divisor (int j, int k)
    // Returns greatest common divisor of j and k
{
    if (j == 0) return k;
    else return Greatest_Common_Divisor (k % j,  j);
}

int main ()
{
    int small, large;

    // Get two integers from user; put them in proper order
    
    cout << "Please input an integer: ";
    cin >> small;
    cout << "Please input another integer: ";
    cin >> large;
    if (small > large)
    {
	// Swap small and large
	
        int temp = small;
	small = large;
	large = temp;
    }

    // Compute GCD of small and large
    
    if ((small < 0) || (large <= 0))  // Can't find GCD
	cout << "\nSorry, both integers must be non-negative, "
	     << "and one must be positive";
    else  // Compute and report GCD
	cout << "\nGCD = " << Greatest_Common_Divisor (small, large)
	     << "\n";
}