#include <fstream>
#include <cmath>
using namespace std;
int gcd(int a, int b)
{ if ((a==0)||(b==0)) return abs(a+b);
  else { int x,y,z;
         x=abs(a);
         y=abs(b);
         for (z=1; z!=0; )
         { z=x%y;
           x=y;
           y=z;
         }
         return x;
       }
}
int main()
{ int a,b;
  ifstream fi;
  fi.open("gcd.in");
  fi>>a>>b;
  fi.close();
  ofstream fo;
  fo.open("gcd.out");
  fo<<gcd(a,b)<<endl;
  fo.close();
  return 0;
}