#include <bits/stdc++.h>
using namespace std;
int a, b, c;
int main() {
  ios_base::sync_with_stdio(false);
  cin >> a >> b >> c;
  int ac = a;
  int bc = b / 2;
  int cc = c / 4;
  if (ac <= bc && ac <= cc)
    cout << ac + ac * 2 + ac * 4;
  else if (bc <= ac && bc <= cc)
    cout << bc + bc * 2 + bc * 4;
  else
    cout << cc * 4 + cc * 2 + cc;
  return 0;
}
