#include "bits/stdc++.h"
using namespace std;
#define int long long
#define REP(i,n) for(int i = 0;i < (int)(n);i++)
#define RREP(i,n) for(int i = (int)n-1;i >= 0;i--)
#define FOR(i,s,n) for(int i = s;i < (int)n;i++)
#define RFOR(i,s,n) for(int i = (int)n-1;i >= s;i--)
#define ALL(a) a.begin(),a.end()
template<class T>inline void out(T t){cout<<t<<"\n";}
template<class T,class... Ts>inline void out(T t,Ts... ts){cout<<t<<" ";out(ts...);}
template<class T>inline bool CHMAX(T&a,T b){if(a<b){a = b;return true;}return false;}
template<class T>inline bool CHMIN(T&a,T b){if(a>b){a = b;return true;}return false;}
constexpr long long INF = 1e18;


signed main(){
	vector<int>dp;
	dp.push_back(1);
	dp.push_back(1);
	int lim = 1e16;
	while(dp.back() < lim)dp.push_back(dp.back()+dp[dp.size()-2]);
	int ma = 0;
	vector<int>a(5);
	REP(i,5)cin >> a[i];
	reverse(ALL(a));
	REP(i,dp.size()-4){
		int t = 0;
		REP(j,5){
			if(dp[i+j]!=a[j])break;
			++t;
		}
		CHMAX(ma,t);
	}
	out(ma);
}