"use strict"

const arg_str = require('fs').readFileSync('/dev/stdin', 'UTF-8')
const args_lines = arg_str.split('\n')
const n = args_lines[0]
const v_array = args_lines[1].split(' ')

const v_array_num = v_array.map(x=>parseInt(x))
const v_array_num_sort = v_array_num.sort((a,b)=>(a-b))

const result = v_array_num_sort.reduce((a,b)=>((a+b)/2))

console.log(result)