#include<stdio.h>
void main()
{
	int a,b;
	printf("輸入兩個正整數：");
	scanf("%d,%d",&a,&b);
	while(a<=0||b<=0){printf("重新輸入：");
	scanf("%d,%d",&a,&b);}
	while(b){
		int r=a%b;
		a=b;b=r;
	}
	printf("%d\n",a);
}