Uses
CRT;
var
n,i:integer;
p:real;
begin
clrscr;
readln(n);
p:=1;
for i:=1 to n do
begin
p:=p*(((i*2)-1)/(i*2));
end;
write(p);
end.
Uses
CRT;
var
n,i:integer;
p:real;
begin
clrscr;
readln(n);
p:=1;
for i:=1 to n do
begin
p:=p*(((i*2)-1)/(i*2));
end;
write(p);
end.