import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

# 複素平面で z -> i conjugate(z) or 1+i conjugate(z)

X,Y = map(int,read().split())

Z = complex(X,Y)

se = set([Z])
answer = -1
for i in range(10):
    if any(z.real == z.imag for z in se):
        answer = i
        break
    se = set(1j * z.conjugate() for z in se) | \
         set((1+1j) * z.conjugate() for z in se)

print(answer)