//  Nikita Golikov, 2023

#include <bits/stdc++.h>

using namespace std;

using uint = unsigned int;
using ll = long long;
using ull = unsigned long long;

#ifdef GOLIKOV
  #include "/Users/golikovnik/contests/debug.h"
#else
  #define debug(...) ;
#endif

template <class A, class B>
bool smin(A& x, B&& y) {
  if (y < x) {
    x = y;
    return true;
  }
  return false;
}

template <class A, class B>
bool smax(A& x, B&& y) {
  if (x < y) {
    x = y;
    return true;
  }
  return false;
}

int main() {
#ifdef GOLIKOV
  assert(freopen("in", "rt", stdin));
  auto _clock_start = chrono::high_resolution_clock::now();
#endif
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  int a, b, c;
  cin >> a >> b >> c;
  int ans = 2 * a;
  if (c >= 2) {
    ans += 3 * (c / 2);
    ans += 2 * b;
  }
  cout << ans << '\n';

#ifdef GOLIKOV
  cerr << "Executed in " << chrono::duration_cast<chrono::milliseconds>(
      chrono::high_resolution_clock::now()
          - _clock_start).count() << "ms." << endl;
#endif
  return 0;
}