function myout(text){console.log(text);}//standard output
function Main(input) {
	input = parseInt(input);
	//input = input.trim().split(" ");
	//input = input.trim().split("\n");
	//input = input.trim().split(" ").map((a)=>Number(a));
	//input = input.trim().split("\n").map((a)=>Number(a));
  var odd = 0;
  for(var i = 1; i <= input; i++){
    if(i % 2 == 1){
       odd++;
       }
  }
  myout(odd / input);
}

Main(require("fs").readFileSync("/dev/stdin", "utf8").trim());
