{programmer:mogtaba amirzade 
url http:\\www.ifjam.com
}
program p8(input,output); {14:while form}
var
i,n:integer;
s:real;
begin {program}
s:=0;
i:=1;
readln(n);
while i<=n do
begin {while}
s:=s+1/i;
i:=i+1;
end; {while}
writeln(s:1);
readln
end. {program}