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