//SESC USU SUDO RM -RF

var a,b,c,d,i:integer;
begin
readln(a);
readln(b);
for i:=1 to 10000 do
  begin
    if i mod 2 = 0 then
    if b-c <> 0 then
    c:=c+1
      else d:=d+1
    else if a-c <> 0 then
    c:=c+1
      else d:=d+1;
  end;
case d of
  1..200000 : writeln ('yes');
  0 : writeln ('no');
  end;
end.

Edited by author 01.12.2012 17:39

Edited by author 01.12.2012 17:39

Edited by author 01.12.2012 17:39

no go