from collections import Counter

a = int(input())
b = list(map(int,input().split()))

dic = {}

for i in range(a):
    number = (bin(b[i])[2:])[::-1].split()
    for j, ch in enumerate(number[0]):
        if(dic.get(j,0)):
            dic[j] += 1
        else:
            dic[j] = 1
for i in range(0,65,1):
    dic[i+1] = dic.get(i+1,0) + dic.get(i,0) // 2
    

result = 0
for i in range(0,65,1):
    a = dic.get(i,0)
    if a > 0:
        a = 1

    result += a * pow(2,i)

print(result)