#include <bits/stdc++.h>

using namespace std;

using ll = long long;

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    array<ll, 5> a{};
    for (int i = 4; i >= 0; --i) {
        cin >> a[i];
    }

    vector<ll> v;
    v.push_back(1);
    v.push_back(1);
    for (int i = 2; ; ++i) {
        v.push_back(v[i - 2] + v[i - 1]);
        if (v.back() > 1000000000000000LL) {
            v.pop_back();
            break;
        }
    }
    
    int ans = 0;
    for (int i = 0; i + 5 <= v.size(); ++i) {
        for (int j = 0; j < 5; ++j) {
            if (v[i + j] != a[j]) break;
            ans = max(ans, j + 1);
        }
    }
    cout << ans << "\n";
    return 0;
}