function Main(input) {
	var data = input.split("\n");
	var n =  data[1].split(" ").map((n) => parseInt(n, 10));
	n = n.sort();
	console.log(n)
	var tmp = 0;
	
	for(var i=0;i < parseInt(data[0])-1; i++){
		tmp = (n[0]+n[1])/2
		n.shift();
		n[0] = tmp;
	}
	console.log(n[0])
}
// Don't edit this line!
Main(require("fs").readFileSync("/dev/stdin", "utf8"));