TONG5 PASCAL

var n,i:longint;s:real;
begin
    assign(input,'tong5.inp');reset(input);
    assign(output,'tong5.out');rewrite(output);
    readln(n);
    s:=0;
    for i:=0 to n do
           s:=s+(2*i+1)/(2*i+2);
    writeln(s:0:2);
end.