#include <iostream>
#include <algorithm>
#include <vector>

using lint = long long;
constexpr lint INF = 1LL << 50;

void solve() {
    std::vector<lint> fib{1, 1};
    while (fib.back() < INF) {
        fib.push_back(fib[fib.size() - 1] + fib[fib.size() - 2]);
    }
    int m = fib.size();

    std::vector<lint> xs(5);
    for (auto& x : xs) std::cin >> x;
    std::reverse(xs.begin(), xs.end());

    int ans = 0;
    for (int i = 0; i + 5 <= m; ++i) {
        for (int j = 0; j < 5; ++j) {
            if (xs[j] != fib[j + i]) break;
            ans = std::max(ans, j + 1);
        }
    }

    std::cout << ans << std::endl;
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}