var
sum:real;
n,f,i:integer;
begin
readln(n);
i:=1;
f:=1;
sum:=1;
while i<n+1 do
f:=f*i;
sum:=sum + (1/f);
i:=i+1;
end;
Writeln(sum:0:2);
end.
var
sum:real;
n,f,i:integer;
begin
readln(n);
i:=1;
f:=1;
sum:=1;
while i<n+1 do
begin
f:=f*i;
sum:=sum + (1/f);
i:=i+1;
end;
Writeln(sum:0:2);
end.