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

int main() {
  ios::sync_with_stdio(false);

  vector<int64_t> A(5);
  for (int i = 0; i < 5; ++i) cin >> A[i];

  vector<int64_t> fib(2, 1);
  while (fib.back() < 1e15) {
    int64_t n = *(fib.end() - 2) + *(fib.end() - 1);
    fib.push_back(n);
  }

  int maxn = 0;
  for (int i = 0; i < fib.size(); ++i) {
    if (fib[i] != A.back()) continue;
    int n = 1;
    while (n < 5 && i + n < fib.size() && fib[i + n] == A[4 - n]) ++n;
    maxn = max(maxn, n);
  }

  cout << maxn << endl;

  return 0;
}