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

int64_t solve(const size_t n, 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;
    }

    if (m == sum_l) {
        uint64_t x = 0;
        for (uint64_t e : l) x += e * e;
        return (m * m - x) / 2;
    }

    const auto [t0, sum_t0] = [&] {
        auto is_ok = [&](uint64_t t) {
            uint64_t sum = 0;
            for (size_t i = 0; i < n; ++i) {
                sum += std::clamp(t, l[i], r[i]);
            }
            return std::make_pair(sum < m, sum);
        };
        
        // binary search
        uint64_t tl = 0, tr = 1000000010;
        assert(is_ok(tl).first and not is_ok(tr).first);

        while (::abs(tl - tr) > 1) {
            uint64_t t = (tl + tr) / 2;
            (is_ok(t).first ? tl : tr) = t;
        }
        return std::make_pair(tl, is_ok(tl).second);
    }();

    uint64_t d = m - sum_t0;
    uint64_t x = 0;
    for (size_t i = 0; i < n; ++i) {
        uint64_t c = std::clamp(t0, l[i], r[i]);
        if (d > 0 and l[i] <= t0 and t0 < r[i]) {
            ++c, --d;
        }
        x += c * c;
    }
    assert(d == 0);
    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;
}