#include<fstream>

using namespace std;

#define input "cmmdc.in"
#define output "cmmdc.out"
ifstream fin (input);
ofstream fout(output);
int main ()
{
    int a,b,div,nr,i;
    fin>>a>>b;
    if(a>b)
    {nr=a;
           div=b;}
    if(b>a)
    {nr=b;
    div=a;}
    for(i=div;i>=1;i--)
    {if(b==a)
    {fout<<0;
    break;
}if(i!=1)
                       if(nr%i==0 && div%i==0)
                       {
                                  fout<<i;
                                  break;
                             }
                             else break;
                                  }if(i=1)
                                  fout<<0;
                                  return 0;
                                  }