def main0(n,m):
  fib=[1,1]
  while len(fib)<n:
    fib.append(fib[-1]+fib[-2])
  kouho=fib[:-2]
  delta=fib[-1]-m
  ans=0
  for i in range(len(kouho)):
    if delta>=kouho[-i-1]:
      delta-=kouho[-i-1]
      ans+=1
  return ans if delta==0 else -1

if __name__=='__main__':
  n,m=map(int,input().split())
  print(main0(n,m))