from collections import deque
def convert_bit(x):
    return bin(x).count("1")

N = int(input())
q = deque([1])
reach =[0 for i in range(N)] 
while q != deque([]):
    pos = q.popleft()
    reach[pos-1] = 1 
    if pos == N:
        print(N)
        exit()
    move = convert_bit(pos)
    for m in [move,-move]:
        next_pos = m + pos
        if not 1 <= next_pos <= N:
            continue 
        if reach[next_pos - 1] == 1:
            q.append(next_pos)
print(-1)