program SumSeries;
var
n, i: integer;
S: real;
begin
write('Enter the value of n: ');
readln(n);

S := 0;

for i := 3 to n step 2 do
begin
S := S + 1 / i;
end;

writeln('Sum of the series for n = ', n, ' is ', S:0:2);
end.