from itertools import combinations
def load():
    return list(map(int, input().split()))

def solve():
    d = 0
    n = int(input())
    numbers = load()
    possibleSubsetSums = []
    for i in range(n + 1):
        for subset in list(combinations(numbers, i)):
            possibleSubsetSums.append(sum(subset))
    for a in possibleSubsetSums:
        d = d | a
    print(d)

def main():
    # t = int(input())
    t = 1
    for i in range(t):
        solve()
if __name__ == "__main__":
    main()