X = int(input())
if X == 0:
    print(1)
    exit()
def bit_count(n):
    cnt = 0
    while n:
        cnt += n & 1
        n >>= 1
    return cnt
for i in range(61):
    N = i ^ X
    if N <= int(1e18) and bit_count(N) == i:
        print(N)
        exit()
print(-1)