Var
y, s, d: real;
i, n, j: integer;
function factorial(N: integer): longint;
begin
if N = 0 then factorial := 1
Else factorial := factorial(N - 1) * N
end;
begin
readln(n);
s := 1;
for i := 2 to n do
begin
d := 1;
for j := 2 to i do
d := d + (1 / j);
s := s + (factorial(i) / d);
end;
write(s);
end.