#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
const int INF = 0x3f3f3f3f;
const ll LINF = 0x3f3f3f3f3f3f3f3fLL;
const double EPS = 1e-8;
const int MOD = 1000000007;
// const int MOD = 998244353;
const int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
const int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U> inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U> inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  vector<ll> a(5); REP(i, 5) cin >> a[i];
  ll lb = 0, ub = accumulate(ALL(a), 0LL);
  while (ub - lb > 1) {
    ll mid = (lb + ub) / 2;
    vector<ll> b(5);
    REP(i, 5) b[i] = mid - a[i];
    function<ll(ll)> f = [&](ll r) {
      vector t(5, 0LL);
      t[0] += r;
      t[4] += r;
      REP(i, 3) {
        ll tmp = max(b[i] - t[i], 0LL);
        t[i] += tmp;
        t[i + 1] += tmp;
      }
      ll tmp = max({b[3] - t[3], b[4] - t[4], 0LL});
      t[3] += tmp;
      t[4] += tmp;
      return accumulate(ALL(t), 0LL) / 2;
    };
    ll l = 0, r = max(b[0], b[4]) + 1;
    while (r - l > 1) {
      ll m = (l + r) / 2;
      (f(m - 1) - f(m) == 1 ? l : r) = m;
    }
    (f(l) <= mid ? lb : ub) = mid;
  }
  cout << lb << '\n';
  return 0;
}