#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
int main() {
	long long limit = 1;
	for (int i = 0; i < 15; ++i) {
		limit *= 10;
	}
	vector<long long> a = { 1, 1, 2 };
	while (a[a.size() - 1] + a[a.size() - 2] <= limit) {
		a.push_back(a[a.size() - 1] + a[a.size() - 2]);
	}
	int n = 5;
	vector<long long> seq(5);
	for (int i = 0; i < 5; ++i) {
		cin >> seq[i];
	}
	int ans = 0;
	for (int i = 1; i <= 5; ++i) {
		vector<long long> subseq(seq.end() - i, seq.end());
		reverse(subseq.begin(), subseq.end());
		int ptr = lower_bound(a.begin(), a.end(), subseq[0]) - a.begin();
		if (i >= 2 && subseq[0] == 1 && subseq[1] != 1) ptr = 1;
		if (ptr + i <= a.size() && subseq == vector<long long>(a.begin() + ptr, a.begin() + ptr + i)) {
			ans = i;
		}
	}
	cout << ans << endl;
	return 0;
}