#pragma GCC optimize("O2")
#include <algorithm>
#include <array>
#include <bit>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cfenv>
#include <cfloat>
#include <chrono>
#include <cinttypes>
#include <climits>
#include <cmath>
#include <compare>
#include <complex>
#include <concepts>
#include <cstdarg>
#include <cstddef>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <deque>
#include <fstream>
#include <functional>
#include <initializer_list>
#include <iomanip>
#include <ios>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <map>
#include <memory>
#include <new>
#include <numbers>
#include <numeric>
#include <ostream>
#include <queue>
#include <random>
#include <ranges>
#include <set>
#include <span>
#include <sstream>
#include <stack>
#include <streambuf>
#include <string>
#include <tuple>
#include <type_traits>
#include <variant>

#define int ll
#define INT128_MAX (__int128)(((unsigned __int128) 1 << ((sizeof(__int128) * __CHAR_BIT__) - 1)) - 1)
#define INT128_MIN (-INT128_MAX - 1)

#define clock chrono::steady_clock::now().time_since_epoch().count()

#ifdef DEBUG
#define dbg(x) cout << (#x) << " = " << x << '\n'
#else
#define dbg(x)
#endif

namespace R = std::ranges;
namespace V = std::views;

using namespace std;

using ll = long long;
using ull = unsigned long long;
using ldb = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
//#define double ldb

template<class T>
ostream& operator<<(ostream& os, const pair<T, T> pr) {
  return os << pr.first << ' ' << pr.second;
}
template<class T, size_t N>
ostream& operator<<(ostream& os, const array<T, N> &arr) {
  for(const T &X : arr)
    os << X << ' ';
  return os;
}
template<class T>
ostream& operator<<(ostream& os, const vector<T> &vec) {
  for(const T &X : vec)
    os << X << ' ';
  return os;
}
template<class T>
ostream& operator<<(ostream& os, const set<T> &s) {
  for(const T &x : s)
    os << x << ' ';
  return os;
}


signed main() {
  ios::sync_with_stdio(false), cin.tie(NULL);

  int t; cin >> t;
  while(t--) {
    int n, m; cin >> n >> m;
    vector<int> l(n), r(n);
    for(int &x : l)
      cin >> x;
    for(int &x : r)
      cin >> x;

    if (accumulate(l.begin(), l.end(), 0ll) <= m and m <= accumulate(r.begin(), r.end(), 0ll)) {
      int mx = *R::partition_point(V::iota(0, m + 1), [&](int x) { 
        int cnt = 0;
        for(int i = 0; i < n; i++)
          cnt += min(max(l[i], x), r[i]);
        return cnt < m;
      });
      for(int i = 0; i < n; i++)
        l[i] = max(l[i], mx - 1);
      int sum = accumulate(l.begin(), l.end(), 0ll);
      for(int i = 0; i < n; i++)
        if (sum < m and l[i] == mx - 1 and l[i] < r[i])
          l[i]++, sum++;
      int ans = m * (m - 1) / 2;
      for(int x : l)
        ans -= x * (x - 1) / 2;
      cout << ans << '\n';
    } else {
      cout << -1 << '\n';
    }
  }

  return 0;
}