Program aaa;
var i,n:integer;sum:real;
Begin
sum:=1;
writeln('Enter n');
readln(n);
for i:=1 to n do
Begin
sum:=sum*(2*i);
end;
writeln(sum);
end.
Program aaa;
var i,n:integer;sum:real;
Begin
sum:=1;
writeln('Enter n');
readln(n);
for i:=1 to n do
Begin
sum:=sum*(2*i);
end;
writeln(sum);
end.