package main

import (
	"fmt"
	"sort"
)

func main() {
	var N int
	fmt.Scan(&N)

	vs := make([]int, N)
	for i := 0; i < N; i++ {
		var a int
		fmt.Scan(&a)
		vs[i] = a
	}

	sort.Ints(vs)
	fmt.Println(vs)
	ret := 0.0
	ret = (float64(vs[0]) + float64(vs[1])) / 2
	if 2 <= N {
		for i := 2; i < N; i++ {
			ret = (ret + float64(vs[i])) / 2
		}
	}
	fmt.Println(ret)
}
