#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
signed main() { 
  ios::sync_with_stdio(false); cin.tie(0);
  vector<long long> fib = {0, 1};
  long long x = 0, y = 1;
  while (x + y <= 1e15) {
    fib.push_back(x + y);
    x = y;
    y = fib.back();
  }
  vector<long long> a(5);
  for (int i = 4; i >= 0; i--) cin >> a[i];
  set<vector<long long>> st;
  vector<long long> vv;
  for (int i = 0; i < 5; i++) {
    vv.push_back(a[i]);
    st.insert(vv);
  }
  int ans = 0;
  for (int i = 0; i < (int) fib.size(); i++) {
    vector<long long> v;
    for (int j = i; j < i + 5 && j < (int) fib.size(); j++) {
      v.push_back(fib[j]);
      if (st.count(v)) {
        ans = max(ans, (int) v.size());
      }
    }
  }
  cout << ans << '\n';
  return 0;
}