#include <stdio.h>

int CMMDC(int a, int b)
{
    int c;
    while (b)
    {
        c = a % b;
        a = b;
        b = c;
    }
    return a;
}

int main()
{
    FILE* fin;
    FILE* fout;
    int a,b;
    fin = fopen("cmmdc.in", "r");
    fout = fopen("cmmdc.out", "w");
    fscanf(fin, "%d %d", &a, &b);
    if(CMMDC(a,b) == 1) fprintf(fout, "%d", 0);
    else
    {
        fprintf(fout, "%d", CMMDC(a,b));
    }
    return 0;
}