gx, gy = map(int, input().split())

def rook_moves(x, y):
    if x == 0 and y == 0:
        return 0
    elif x == 0 or y == 0:
        return 1
    else:
        return 2

def bishop_moves(x, y):
    if (x + y) % 2 != 0:
        return -1  # impossible for bishop
    if x == 0 and y == 0:
        return 0
    elif abs(x) == abs(y):
        return 1
    else:
        return 2

print(min(rook_moves(gx, gy), bishop_moves(gx, gy)))