var a,b,r:longint;
begin
 assign(input,'euclid2.in'); reset(input);
 assign(output,'euclid2.out'); rewrite(output);
  readln(a,b); r:=a mod b;
  while r<>0 do begin
   a:=b; b:=r; r:=a mod b;
  end;
  writeln(b);
 close(input); close(output);
end.