program cel_mai_mare_divizor_comun;
var c,a,b:longint;
    f,g:text;
    r:byte;
begin
 assign(f,'cmmdc.in');
 reset(f);
 assign(g,'cmmdc.out');
 rewrite(g);
 readln(f,a);
 read(f,b);
 while b<>0 do begin
  r:=a mod b;
  a:=b;
  b:=r;
 end;
 if a=1 then write(g,'0')
        else write(g,a);
 close(f);
 close(g);
end.