var
i,j,N:longint;
begin
readln(N);
if N = 1 then
begin
writeln('BUKAN');
end
else
begin
for i:= 1 to N do
begin
if (N mod i = 0) then
begin
j:=j+1;
end;
if j = 2 then
begin
writeln('YA');
end
else
begin
writeln('BUKAN');
end;
end;
end;
end.
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