#pragma GCC optimize("O3,unroll-loops")

#include <iostream>
#include <vector>
#include <array>
#include <string>
#include <algorithm>
#include <iomanip>
#include <map>
#include <deque>
#include <set>
#include <random>
#pragma GCC target("avx2")

using namespace std;
#define ll long long
#define ld long double

void solve() {
    int n, m, c;
    cin >> n >> m >> c;
    vector <ll> a(n + 1);
    vector <ll> b(m + 1);
    for (int i = 1; i <= n; ++i) cin >> a[i];
    for (int i = 1; i <= m; ++i) cin >> b[i];
    for (int i = 1; i <= m; ++i) b[i] += b[i - 1];
    for (int i = 1; i <= n; ++i) a[i] += a[i - 1];

    vector <ll> dp(n + 1);

    auto recalc = [&](int l, int r) {
        ll sum = a[r + 1] - a[l];
        auto it = upper_bound(b.begin(), b.end(), sum);
        return it - b.begin() - 1 + dp[l] - c;
    };

    auto recalc_in_double = [&](int l, int r) -> ld {
        ll sum = a[r + 1] - a[l];
        auto it = upper_bound(b.begin(), b.end(), sum);

        int me = it - b.begin() - 1;
        if (me == m || sum == b[me]) return me + dp[l] - c;
        return dp[l] - c + me + (ld)(sum - b[me]) / (ld)(b[me + 1] - b[me]);
    };

    deque <array <int, 3>> st;
    st.push_back({1, n, 0});

    for (int i = 1; i <= n; ++i) {
        dp[i] = recalc(st.front()[2], i - 1);
        if (i == n) break;
        st.front()[0]++;
        if (st.front()[0] > st.front()[1]) st.pop_front();

        int new_l = n + 1;

        while (!st.empty()) {
            if (recalc_in_double(i, st.back()[0] - 1) > recalc_in_double(st.back()[2], st.back()[0] - 1)) {
                new_l = st.back()[0];
                st.pop_back();
            } else {
                break;
            }
        }

        if (!st.empty()) {
            int bl = st.back()[0];
            int br = st.back()[1] + 1;

            while (br - bl > 1) {
                int bm = (bl + br) / 2;
                if (recalc_in_double(i, bm - 1) > recalc_in_double(st.back()[2], bm - 1)) {
                    br = bm;
                } else {
                    bl = bm;
                }
            }

            if (br != st.back()[1] + 1) {
                new_l = br;
                st.back()[1] = bl;
            }
        }

        if (new_l != n + 1) {
            st.push_back({new_l, n, i});
        }
    }

    cout << dp.back() << "\n";
}

signed main() {
    if (1) {
        ios_base::sync_with_stdio(false);
        cin.tie(nullptr);
    }
    int t;
    cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}

/*
2
5 4 2
1 0 3 1 2
0 1 1 2
4 5 1
7 16 23 4
1 3 6 20 20
 */