#include <stdio.h>
int main(void)
{
	int a = 24;
	int b = 18;
	int c = 0;
	scanf_s("%d,%d", &a ,& b);
	while (c = a % b )
	{
		a = b;
		b = c;
	}
	printf("%d", b);
	return 0;
}

此时结果就为最大公约数