#include <algorithm>
#include <cassert>
#include <iostream>
#include <numeric>
#include <vector>
#include <map>

int64_t solve(const size_t, const uint64_t m, const std::vector<uint64_t>& l, const std::vector<uint64_t>& r) {
    const uint64_t sum_l = std::accumulate(l.begin(), l.end(), uint64_t(0));
    const uint64_t sum_r = std::accumulate(r.begin(), r.end(), uint64_t(0));

    if (m < sum_l or m > sum_r) {
        return -1;
    }

    std::map<int64_t, size_t> inout;
    for (uint64_t e : l) ++inout[e];
    for (uint64_t e : r) --inout[e];

    uint64_t x = 0;
    for (uint64_t e : l) x += e * e;

    uint64_t sum = sum_l;
    size_t num = 0;
    for (uint64_t t0 = 0; ; ++t0) {
        if (auto it = inout.find(t0); it != inout.end()) {
            num += it->second;
        }
        uint64_t d = std::min(m - sum, num);
        x += (2 * t0 + 1) * d;
        sum += d;
        if (sum == m) {
            return (m * m - x) / 2;
        }
    }
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    size_t t;
    std::cin >> t;
    
    while (t --> 0) {
        size_t n;
        uint64_t m;
        std::cin >> n >> m;

        std::vector<uint64_t> l(n), r(n);
        for (auto& e : l) std::cin >> e;
        for (auto& e : r) std::cin >> e;

        std::cout << solve(n, m, l, r) << '\n';
    }

    return 0;
}