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

# 複素平面で 1+i 倍
# 高々 8 回

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

INF = 100

def F(X,Y):
    for i in range(20):
        if X == Y:
            return i
        X,Y = X+Y, X-Y
    return INF

a = F(X,Y)
b = F(Y,X) + 1
x = min(a,b)

if x == INF:
    x = -1
print(x)