function Main(input) {
	var n = parseInt(input, 10);
	var results = [];
	for (var i = 1; i <= n; i++) {
		if (i % 2 != 0) {
			results.push(i);
		}
	}
	console.log(results.length / n);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));