#define _CRT_SECURE_NO_WARNINGS
#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
#define int    long long 
typedef pair<int, int>pii;
typedef pair<char, int>pci;
typedef pair<int, pii>piii;
const int mod = 998244353;
const int N = 5e5 + 100;
int ksm(int a, int b) { if (a == 0 && b == 0)return 1; int ans = 1; while (b) { if (b % 2)ans = (ans * a) % mod; a = (a * a) % mod; b >>= 1; }return ans; }
int sqrtt(int x) { int l = 0, r = 3e9; while (l < r) { int mid = (l + r + 1) >> 1; if (mid * mid == x)return mid; else if (mid * mid > x)r = mid - 1; else l = mid; }return l; }
int p[200010];
int cnt[200010];
int n, m, k;
bool check(int x)
{
    for (int i = 1; i <= n; i++)cnt[i] = 0;
    for (int i = 1, tot = 0; i <= n && tot < x; i++)
    {
        for (int j = 1; j <= m && tot < x; j++,tot++)
        {
            cnt[p[(i - 1) * m + j] / m + 1]++;
        }
    }
    int mn = 1e8;
    for (int i = 1; i <= n; i++)
    {
        if (mn > m - cnt[i])
        {
            mn = m - cnt[i];
        }
    }
    return mn <= k;
}
void solve()
{
    cin >> n >> m >> k;
    for (int i = 1; i <= n; i++)for (int j = 1; j <= m; j++)cin >> p[(i - 1) * m + j];
    int l = m, r = n * m;
    while (l < r)
    {
        int mid = l + r  >> 1;
        if (!check(mid))l = mid + 1;
        else r = mid ;
    }
    cout << l << endl;
    return;
}

signed main()
{

    ios::sync_with_stdio(0); cout.tie(0); cin.tie(0);
    int t = 1;
    cin >> t;
    while (t--) {
        solve();
    }
}