#include <iostream>
#include <vector>
using namespace std;
int main(void) {
	vector<long long> a(5);
	for (int i = 4; i >= 0; --i) cin >> a[i];
	vector<long long> fib(100, -1);
	fib[0] = 1, fib[1] = 1;
	int cnt = 2;
	while (1) {
		fib[cnt] = fib[cnt - 1] + fib[cnt - 2];
		if (fib[cnt] > 1e15) break;
		++cnt;
	}
	cnt = 0;
	int max_cnt = 0;
	for (int i = 0; i < 5; ++i) {
		for (int j = 0; j < fib.size(); ++j) {
			cnt = 0;
			for (int k = 0; k <= i; ++k) {
				if (a[k] == fib[k + j]) ++cnt;
				else break;
			}
			max_cnt = max(cnt, max_cnt);
		}
	}
	cout << max_cnt << endl;
	return 0;
}