import Foundation

let n = Int(readLine()!)!
let nArr = readLine()!.characters.split(separator: " ").map({ Int(String($0))! })
var m = 0.0

for (i, c) in nArr.sorted(by: >).enumerated()
{
    m = m + (Double(c) * pow(2.0, Double(i)))
}

print(Int(m))