using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;
using System.Runtime.Intrinsics.Arm;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var a = new long[5];
        for (var i = 0; i < 5; ++i) a[4 - i] = long.Parse(ReadLine());
        var max = a.Max();
        var fib = new List<long>{ 1, 1 };
        while (fib[^1] <= max) fib.Add(fib[^2] + fib[^1]);
        var ans = 0;
        for (var i = 0; i < fib.Count; ++i)
        {
            if (a[0] != fib[i]) continue;
            var tmp = 1;
            for (var j = 1; j < a.Length; ++j)
            {
                if (a[j] == fib[i + j]) ++tmp;
                else break;
            }
            ans = Math.Max(ans, tmp);
        }
        WriteLine(ans);
    }
}