#include <cstdio>
using namespace std;
/*Files*/
FILE *in = fopen("cmmdc.in", "r");
FILE *out = fopen("cmmdc.out", "w");
/*Typedefs*/
typedef unsigned short int usi_t;

inline usi_t gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }

int main()
{
    int a, b;
    usi_t result;

    fscanf(in, "%d", &a);
    fscanf(in, "%d", &b);
    result = gcd(a,b);
    fprintf(out, "%hu", result == 1 ? 0 : result );
    return 0;
}