#pragma GCC optimize(2)
#pragma GCC optimize(3, "Ofast", "inline")
#include <bits/stdc++.h>
using namespace std;
#define x first
#define y second
#define int long long
#define endl '\n'
using i128 = __int128;
using i64 = long long;
using f128 = long double;
using u64 = unsigned long long;
using pii = pair<int, int>;
const int INF = 0x3f3f3f3f, mod = 1e9 + 7;
const i64 inf = 2e18;
//-------------------------------------------
struct node
{
    int l, r, id;
};

struct st_tree
{
    int n;
    vector<int> p;
    st_tree(int _n) : p(_n + 1), n(_n) {};
    int lowbit(int x)
    {
        return x & -x;
    }

    void add(int u, int d)
    {
        while (u <= n)
            p[u] += d, u += lowbit(u);
    }

    int find(int u)
    {
        int sum = 0;
        while (u > 0)
        {
            sum += p[u], u -= lowbit(u);
            // cout << sum <<endl;
        }
        return sum;
    }
};

void solve()
{
    int n, m;
    cin >> n >> m;
    st_tree stt(n + 1);
    vector<int> a(n + 1);
    map<int, vector<int>> id;
    map<int, int> last;
    for (int i = 1; i <= n; i++)
    {
        cin >> a[i];
        id[a[i]].push_back(i);
    }

    vector<node> vec;

    for (int i = 1; i <= m + 1; i++)
    {
        int l = 1;
        if (id.count(i))
        {
            auto v = id[i];
            for (auto u : v)
            {
                if (u - l > 0)
                {
                    vec.push_back({l, u - 1, i});
                }
                l = u + 1;
            }
        }
        if (n - l > 0)
            vec.push_back({l, n, i});
    }

    sort(vec.begin(), vec.end(), [&](node a, node b)
         { return a.r < b.r; });
    int lastr = 0, ans = -inf;
    for (auto [l, r, id] : vec)
    {
        while (lastr < r)
        {
            lastr++;
            if (last.count(a[lastr]))
            {
                stt.add(last[a[lastr]], -1);
            }
            stt.add(lastr, 1);
            last[a[lastr]] = lastr;
        }
        // cerr << l << " " << r << " " << stt.find(r) - stt.find(l - 1) << " " << id << endl;
        ans = max(ans, stt.find(r) - stt.find(l - 1) - id);
    }

    cout << ans << endl;
}
signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int T = 1;
    cin >> T;
    for (int i = 1; i <= T; i++)
        solve();
    return 0;
}