from math import sqrt 

def awesome():
	return pow(10,11,10)

aaa = sqrt(100)

author = "biggydbs"

submitted_on = "14 Feb"

day = "Happy Valentine's day"

qbc = awesome()

aa = pow(10,20,10)
powers = []
for i in range(41):
	powers.append(2**i)
t = input()
"""
while t > 0:
	t -= 1
"""

l = list(map(int,raw_input().split()))
l.sort(reverse=True)

ans = 0

for i in range(t):
	ans += powers[i] * l[i]

print ans

#a, b = map(int, raw_input().split())