#include <bits/stdc++.h>

using namespace std;
using pi = pair<int, int>;
constexpr int INF = 1e9 + 7;

struct s_tr {
    vector<int> s;

    s_tr(int n) {
        s.resize(4 * n, 0);
    }

    void upd(int v, int l, int r, int k, int x) {
        if (l + 1 == r) {
            s[v] = x;
            return;
        }
        int m = (r + l) / 2;
        if (k < m) {
            upd(v * 2 + 1, l, m, k, x);
        } else upd(v * 2 + 2, m, r, k, x);
        s[v] = s[v * 2 + 1] + s[v * 2 + 2];
    }

    int get(int v, int l, int r, int lq, int rq) {
        if (l >= rq || lq >= r) {
            return 0;
        }
        if (l >= lq && r <= rq) {
            return s[v];
        }
        int m = (r + l) / 2;
        return get(v * 2 + 1, l, m, lq, rq) + get(v * 2 + 2, m, r, lq, rq);
    }
};

void solve() {
    int n, m;
    cin >> n >> m;
    m = min(m, n + 2);
    vector<int> a(n);
    vector<vector<int>> all(m + 1);
    for (int i = 0; i <= m; ++i)all[i].push_back(-1);
    for (auto &i: a)cin >> i, --i, i = min(i, m - 1);
    for (int i = 0; i < n; ++i) { all[a[i]].push_back(i); }
    for (int i = 0; i <= m; ++i) all[i].push_back(n);
    int res = -1;
    vector<vector<pair<int, int>>> Q(n);
    for (int i = 0; i <= m; ++i) {
        for (int j = 0; j + 1 < all[i].size(); ++j) {
            int l = all[i][j] + 1, r = all[i][j + 1] - 1;
            if (r >= l) {
                Q[r].push_back({l, i + 1});
            }
        }
    }
    s_tr tree(n);
    vector<int> last(m + 1, -1);
    for (int i = 0; i < n; ++i) {
        if (~last[a[i]]) {
            tree.upd(0, 0, n, last[a[i]], 0);
        }
        tree.upd(0, 0, n, i, 1);
        for (auto &[l, mex]: Q[i]) {
            res = max(res, tree.get(0, 0, n, l, i + 1) - mex);
        }
        last[a[i]] = i;
    }
    cout << res << "\n";
}

int main() {
    cin.tie(0)->sync_with_stdio(false);
    int t;
    cin >> t;
    while (t--)solve();
}