#include <bits/stdc++.h>
using namespace std;
long long a, b, c;
int vis[12];
bool ok(long long mid, int x) {
  long long m = mid % 7;
  int day = x;
  long long res[5];
  res[1] = mid / 7;
  res[2] = mid / 7;
  res[3] = mid / 7;
  res[1] *= 3;
  res[2] *= 2;
  res[3] *= 2;
  while (m--) {
    res[vis[day]]++;
    day++;
    day %= 7;
  }
  return res[1] <= a && res[2] <= b && res[3] <= c;
}
long long ans(int x) {
  long long st = 0, en = 1e12;
  while (st < en) {
    long long mid = (st + en) / 2;
    if (ok(mid, x))
      st = mid + 1;
    else
      en = mid;
  }
  return st;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin >> a >> b >> c;
  vis[0] = 2;
  vis[1] = 1;
  vis[2] = 1;
  vis[3] = 2;
  vis[4] = 3;
  vis[5] = 1;
  vis[6] = 3;
  long long mx = 0;
  for (int i = 0; i < 7; i++) {
    mx = max(mx, ans(i));
  }
  cout << --mx << "\n";
  return 0;
}
