import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(10 ** 7)

x, y = map(int, readline().split())
if x == y:
    print(0)
elif x == 0:
    print(2)
elif y == 0:
    print(1)
elif abs(x) == abs(y):
    print(3)
else:
    print(-1)