#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:256000000")
using namespace std;
const int INF = (int)(1e9 + 1e6);
const long long LINF = (long long)(4e18);
const double EPS = 1e-14;
mt19937 ggen;
void solve();
int main() {
  iostream::sync_with_stdio(false);
  cin.tie(0);
  ggen = mt19937(1337);
  solve();
}
void solve() {
  int a, b, c;
  cin >> a >> b >> c;
  int tt = min({a, b / 2, c / 4});
  cout << tt + tt * 2 + tt * 4;
}
