def main():
    import sys
    input = sys.stdin.read().split()
    idx = 0
    N = int(input[idx])
    idx += 1
    T = int(input[idx])
    idx += 1
    A = list(map(int, input[idx:idx + N]))
    
    current_states = {T: 0}
    for a in A:
        next_states = {}
        for x in current_states:
            # Process AND
            new_x = x & a
            delta = x - new_x
            new_score = current_states[x] + delta
            if new_x in next_states:
                if new_score > next_states[new_x]:
                    next_states[new_x] = new_score
            else:
                next_states[new_x] = new_score
            # Process OR
            new_x = x | a
            delta = new_x - x
            new_score = current_states[x] + delta
            if new_x in next_states:
                if new_score > next_states[new_x]:
                    next_states[new_x] = new_score
            else:
                next_states[new_x] = new_score
        current_states = next_states
    
    print(max(current_states.values()))

if __name__ == '__main__':
    main()