#include <iostream>

using namespace std;

void maxCommonDivisor(int a,int b);

int main ()

{     int a,b;    cin >> a >> b ;    maxCommonDivisor(a,b);    return 0;}

//运用辗转相除法

void maxCommonDivisor(int a,int b)

{     int t,c;    if (a<b)    {         t=a;        a=b;        b=t;    }    c=a-b;    if (a%c==0&&b%c==0)    cout <<c << endl ;    else    {         a=b;        b=c;       maxCommonDivisor(a,b);    }

}