C++ :

#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
vector<int> score[N + 2], a, b;
bool cmp(int i, int j) {
    return i > j;
}
int main() {
    int m, n, k;
    cin >> m >> n >> k;
    a.resize(n), b.resize(n);
    for (int i = 0; i < n; i++) cin >> a[i];
    for (int i = 0; i < n; i++) {
        cin >> b[i];
        score[a[i]].emplace_back(b[i]);
    }
    vector<int> need(m + 2);
    int ans = 0, mx_meed = 0, mx_need_i = -1;
    for (int i = 1; i <= m; i++) {
        sort(score[i].begin(), score[i].end(), cmp);
        int sum = 0;
        for (int j = 0; j < (int)score[i].size(); j++) {
            sum += score[i][j];
            if (sum >= k) {
                need[i] = j + 1;
                break;
            }
        }
        if (sum < k) {
            puts("-1");
            return 0;
        }
        ans += need[i];
        if (need[i] > mx_meed) {
            mx_meed = need[i], mx_need_i = i;
        }
    }
    if (mx_meed - 1 <= ans - mx_meed) {
        cout << ans << endl;
        return 0;
    }
    int last = 0;
    for (int i = 1; i <= m; i++)
        if (i!= mx_need_i)
            last += score[i].size() - need[i];
    cout << (mx_meed - 1 <= ans - mx_meed - last? ans - last : -1) << endl;
    return 0;
}