function Main(input) {
	var data = input.split("\n");
	var kazu = parseInt(data[0],10);
	var n =  data[1].split(" ").map((n) => parseInt(n, 10));
	
	n.sort(function(a, b) {
		return a-b;
	});
	
	var tmp = 0;
	
	for(var i=0;i < kazu -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"));