program ideone;
var
m,n : longint;
begin
m:=1;
readln(n);
if (m = n) then begin
writeln('ya');
end;
while m < n do begin
m := m*2;
if (m=n) then begin
writeln('ya');
end;
end;
if (m > n) and (n >= 1) then begin
writeln('bukan')
end;
end.
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