{programmer:mogtaba amirzade 
url http:\\www.ifjam.com
}
program p9(input,output); {14:repeat}
var
i,n:integer;
s:real;
begin
s:=0;
i:=1;
readln(n);
repeat
s:=s+1/i;
i:=i+1;
until i>n;
writeln(s:1);
readln
end.