#include <bits/stdc++.h>
using namespace std;
const int MAX = 1e6 + 5;
int a, b, c;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> a >> b >> c;
  int sol = 0;
  while (a) {
    if (a * 2 <= b && a * 4 <= c) {
      sol += (a + (a * 2) + (a * 4));
      cout << sol << "\n";
      return 0;
    }
    a--;
  }
  cout << sol << "\n";
  return 0;
}
