#include <stdio.h>
#include <stdlib.h>

int gcd(int x, int y) {
    int r;

    r = x % y;
    while (r > 0) {
	printf("x = %d, y = %d, r = %d\n", x, y, r);
	x = y;
	y = r;
	r = x % y;
    }
    return y;
}

int main(int argc, char *argv[]) {
    int a, b;

    if (argc <= 2) {
	printf("引数が足りません\n");
	return 1;
    };
    a = strtol(argv[1], NULL, 10);
    b = strtol(argv[2], NULL, 10);
    printf("gcd(%d, %d) = %d\n", a, b, gcd(a, b));
    return 0;
}