#yuki954

f=[1,1,2,3]
while f[-1]<=10**15:
 f.append(f[-1]+f[-2])
a=[int(raw_input()) for i in range(5)]
a.reverse()
res=0
for i in range(6):
 for j in range(len(f)-i):
  if a[:i]==f[j:j+i]:
   res=max(res,i)
print res