var x:integer;
var y:real;
begin
readln(x);
if x mod 2 = 0 then
y:= x/2
else
y:= x*x;
writeln(y);
end.
var x:integer;
var y:real;
begin
readln(x);
if x mod 2 = 0 then
y:= x/2
else
y:= x*x;
writeln(y);
end.