#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define FOR(i,b,e) for (int i=(int)(b); i<(int)(e); i++)
#define ALL(x) (x).begin(), (x).end()

const double PI = acos(-1);

vector<long long> fibs() {
  long long a = 1, b = 0;
  vector<long long> ret;
  while (a <= 1e16) {
    ret.push_back(a);
    a = a + b;
    b = a - b;
  }
  return ret;
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  vector<long long> f = fibs();
  vector<long long> a(5);
  REP (i, 5) cin >> a[i];
  reverse(ALL(a));

  int ret = 0;
  REP (i, f.size()) {
    int tmp = 0;
    REP (j, 5) {
      if (i+j < f.size() && a[j] == f[i+j])
        ++tmp;
      else
        break;
    }
    ret = max(ret, tmp);
  }
  
  cout << ret << endl;
  
  return 0;
}