#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 1e5 + 7;
ll a[MAXN], pre[MAXN], n, k, lim, t, ans;

bool check(ll x){
    bool kt = false;
    for(int i = 0; i <= n; i++) if(k * pre[n] - (x * pre[n] + pre[i]) >= lim){
        ans = x * n + i + 1;
        kt = 1;
    }
    if(kt) return 1;
    return 0;
}


int main(){
    ios_base::sync_with_stdio(0);
    cout.tie(0);
    cin.tie(0);
    cin >> t;
    while(t--){
        cin >> n >> k >> lim;
        for(int i = 1; i <= n; i++){
            cin >> a[i];
            pre[i] = pre[i - 1] + a[i];
        }
        ll L = 0, R = k - 1;
        ans = 0;
        while(L <= R){
            int mid = (L + R) / 2;
            if(check(mid))L = mid + 1;
            else R = mid - 1;
        }
        cout << ans << endl;
        for(int i = 1; i <= n; i++) pre[i] = a[i] = 0;
    }
}