#include <bits/stdc++.h>
#include <iostream>
using namespace std;
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define rep(i,a,b) for(LL i = a;i<b; i++)
#define rrep(i,a,b) for(LL i = a;i>b; i--)
#define tobirep(i,a,b,c) for(LL i = a;i<b; i+=c)
#define tobirrep(i,a,b,c) for(LL i = a;i>b; i-=c)
#define INF ((1LL<<62)-(1LL<<31))
#define ooki 9223372036854775807
#define tii -9223372036854775808
typedef long long LL;
int main(){
   ios::sync_with_stdio(0);cin.tie(nullptr);
   LL fib[75];
    fib[0] = 1;
    fib[1] = 1;
    for (int i = 2; i < 75; i++) {
        fib[i] = fib[i - 1] + fib[i - 2];
    }

    vector<LL> a(5);
    for (int i = 0; i < 5; i++) {cin >> a[i];}
    reverse(a.begin(), a.end());

    int maxi = 0;
    for (int i = 0; i < 70; i++) {
        int cnt = 0;
        for (int j = 0; j < 5; j++) {
            if (a[j] != fib[i + j]) break;
            cnt++;
        }
        maxi = max(maxi, cnt);
    }
    cout << maxi << endl;
  
}