## https://yukicoder.me/problems/no/3276


def solve(N):
    array = []
    while N > 0:
        array.append(N % 2)
        N //= 2

    p_count = sum(array)
    if p_count == 1:
        return -1

    answer = 0    
    f = False
    for i in range(len(array)):
        x = 2 ** i
        if array[i] == 1:
            if not f:
                answer += x
                f = True
            else:
                return answer
        else:
            if f:
                answer += x


def main():
    T = int(input())
    answers = []
    for _ in range(T):
        N = int(input())
        ans = solve(N)
        answers.append(ans)

    for ans in answers:
        print(ans)








if __name__ == "__main__":
    main()