#include <cstdio>
using namespace std;

int cmmdc(int a,int b){
    if(a==b)
        return a;
    else if(a>b)
        return cmmdc(a-b,b);
    else
        return cmmdc(a,b-a);
}
int main()
{
    freopen("cmmdc.out","w",stdout);
    freopen("cmmdc.in","r",stdin);
    int a,b,c;
    scanf("%d",&a,&b);
    c=cmmdc(a,b);
    if(c==1)
        printf("0");
    else
        printf("%d",c);
    return 0;
}