import times, strutils, sequtils, math, algorithm, tables, sets, lists, intsets
import critbits, future, strformat, deques
template `max=`(x,y) = x = max(x,y)
template `min=`(x,y) = x = min(x,y)
template `mod=`(x,y) = x = x mod y
template scan2 = (scan(), scan())
template scan3 = (scan(), scan())
let read* = iterator: string {.closure.} =
    while true: (for s in stdin.readLine.split: yield s)
proc scan(): int = read().parseInt
proc scanf(): float = read().parseFloat
proc toInt(c:char): int =
    return int(c) - int('0')



proc solve():int=
  var
    a = newseqwith(5,scan().int64).reversed()
    mx = 97
    fib = newseqwith(mx,0i64)
  fib[0]=1
  fib[1]=1
  fib[2]=2
  fib[3]=3
  fib[4]=5
  fib[5]=8
  for i in 0..<5:
    for l in 1..5:
      if fib[i..<i+l] == a[0..<l]:
        result.max=l
  for i in 6..<mx:
    fib[i] = fib[i-1]+fib[i-2]
    #echo fib[i]
    if fib[i-5]==a[0]:
      for l in 1..5:
        if fib[i-5..<i-5+l] == a[0..<l]:
          result.max=l
      break
    
  
  
  

  
echo solve()