#include <bits/stdc++.h>
using namespace std;
template <class T>
ostream& operator<<(ostream& os, const vector<T>& v) {
  for (T i : v) os << i << ' ';
  return os;
}
template <class T>
ostream& operator<<(ostream& os, const set<T>& v) {
  for (T i : v) os << i << ' ';
  return os;
}
template <class T, class S>
ostream& operator<<(ostream& os, const pair<T, S>& v) {
  os << v.first << ' ' << v.second;
  return os;
}
template <class T, class S>
ostream& operator<<(ostream& os, const map<T, S>& v) {
  for (auto i : v) os << '(' << i.first << "=>" << i.second << ')' << ' ';
  return os;
}
template <class T, class S>
ostream& operator<<(ostream& os, const unordered_map<T, S>& v) {
  for (auto i : v) os << '(' << i.first << "=>" << i.second << ')' << ' ';
  return os;
}
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC target( \
    "avx2,sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
const long long mod = 1e9 + 7;
long long takemod(long long a) { return ((a % mod) + mod) % mod; }
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long fast_exp(long long base, long long expo) {
  long long res = 1;
  while (expo > 0) {
    if (expo & 1) res = (res * base) % mod;
    base = (base * base) % mod;
    expo >>= 1;
  }
  return res;
}
long long modinv(long long a) { return takemod(fast_exp(takemod(a), mod - 2)); }
void solve() {
  long long a1, b1, c1, a2, b2, c2;
  cin >> a1 >> b1 >> c1 >> a2 >> b2 >> c2;
  long long ans = min(c1, b2) * 2;
  long long temp1 = min(c1, b2);
  c1 -= temp1;
  b2 -= temp1;
  long long temp2 = min(c2, a1);
  c2 -= temp2;
  a1 -= temp2;
  long long temp3 = min(c1, c2);
  c1 -= temp3;
  c2 -= temp3;
  long long temp4 = min(b1, c2);
  ans -= temp4 * 2;
  b1 -= temp4;
  c2 -= temp4;
  long long temp5 = min(c1, a2);
  c1 -= temp5;
  a2 -= temp5;
  cout << ans << "\n";
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  int t = 1;
  cin >> t;
  while (t--) {
    solve();
  }
  return 0;
}
