var number: integer;
begin
readln(number);
if number mod 2 = 0 then
number := number + 1
else number := number + 2;
writeln(number);
end.
var number: integer;
begin
readln(number);
if number mod 2 = 0 then
number := number + 1
else number := number + 2;
writeln(number);
end.