#include <iostream>

using namespace std;

int main() {
  int nr, ng, nb, hr, hg, hb, hrg, hgb;
  cin >> nr >> ng >> nb >> hr >> hg >> hb >> hrg >> hgb;
  int ret = 0;
  {
    int use = min(nr, hr); nr -= use; hr -= use;
  }
  {
    int use = min(ng, hg); ng -= use; hg -= use;
  }
  {
    int use = min(nb, hb); nb -= use; hb -= use;
  }
  {
    int use = min(nr, hrg); nr -= use; hrg -= use; ret += use;
  }
  {
    int use = min(nb, hgb); nb -= use; hgb -= use; ret += use;
  }
  {
    int use = min(ng, hrg); ng -= use; hrg -= use; ret += use;
  }
  {
    int use = min(ng, hgb); ng -= use; hgb -= use; ret += use;
  }
  if(nr || ng || nb) ret = -1;
  cout << ret << "\n";
}