#include <bits/stdc++.h>
using namespace std;

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  int n = 5;
  vector<long long> a(n);
  for (int i = n; i--; ) {
    cin >> a[i];
  }
  vector<long long> fib{1, 1};
  while (fib.back() < 1e15) {
    fib.push_back(fib[(int)fib.size() - 2] + fib.back());
  }
  int m = fib.size();
  for (int k = n; k >= 0; --k) {
    bool ok = false;
    for (int j = 0; j + k <= m; ++j) {
      if (vector<long long>(begin(a), begin(a) + k) == vector<long long>(begin(fib) + j, begin(fib) + j + k)) {
        ok = true;
        break;
      }
    }
    if (ok) {
      cout << k << '\n';
      return 0;
    }
  }
}