length = int(input())
numbers = [int(j) for j in input().split()]

max_ones = []
for number in numbers:
    bin_number = bin(number)[:1:-1]
    for i, digit in enumerate(bin_number):
        if i >= len(max_ones):
            max_ones.append(0)
        if digit == "1":
            max_ones[i] += 1

i = 0
carry = 0
while i < len(max_ones):
    max_ones[i] += carry
    carry = max_ones[i] // 2
    if carry and i == len(max_ones) - 1:
        max_ones.append(0)
    i += 1

result = 0
for i, n in enumerate(max_ones):
    if n:
        result += 2 ** i
print(result)