x, y = map(int, input().split())
dist = {}
que = [(0, x, y)]
for n, x, y in que:
    if -100<=x<=100 and -100<=y<=100 and (x, y) not in dist:
        if x == y:
            print(n)
            break
        dist[x, y] = n
        que += [(n+1, x+y, x-y), (n+1, y, x)]
else:
    print(-1)