// 14-2
#include <stdio.h>

int gcm(int x, int y);

int main()
{
    int x, y, g;
    printf("１つ目の値を入力\n");scanf("%d", &x);
    printf("２つ目の値を入力\n");scanf("%d", &y);
    if (x * y == 0) {
        printf("ゼロを指定しないでください\n");
        return 1;
    }
    g = gcm(x, y);
    if (g < 0) {
        g = -g;
    }
    printf("%d gcm %d = %d\n", x, y, g);
    return 0;
}

int gcm(int x, int y)
{
    int z;
    while ((z = x % y)) {
        x = y;
        y = z;
    }
    return y;
}