#include <iostream>
#include <vector>
#include <array>
#include <list>
#include <string>
#include <stack>
#include <queue>
#include <deque>
#include <unordered_map>
#include <unordered_set>
#include <tuple>
#include <memory>
#include <cmath>
#include <algorithm>
#include <functional>
#include <iomanip>
#include <numeric>
#include <climits>
#include <cfloat>
#include <cassert>
#include <random>

int main() {
	std::vector<long long int> a(5); for (auto& n : a) std::cin >> n;
	std::reverse(a.begin(), a.end());
	if (a[0] == 1 && a[1] == 1) {
		int i = 2;
		for (; i < 5 && a[i - 1] + a[i - 2] == a[i]; ++i) {}
		std::cout << i << std::endl;
	}
	else {
		long long int n = 1, m = 2;
		while (n < a.front()) {
			m += n;
			n = m - n;
		}
		if (n != a.front()) {
			std::cout << 0 << std::endl;
		}
		else if (m != a[1]) {
			std::cout << 1 << std::endl;
		}
		else {
			int i = 2;
			for (; i < 5 && a[i - 1] + a[i - 2] == a[i]; ++i) {};
			std::cout << i << std::endl;
		}
	}
}