#include <stdio.h>
// Euclid's algorithm
int GCD(int x, int y)
{
if (y == 0)
return x;
return GCD(y, x % y);
}
int main()
int a, b;
printf("Input two numbers:\n");
scanf("%d %d", &a, &b);
printf("Greatest common divisor: %d\n", GCD(a, b));