#include <bits/stdc++.h>

using namespace std;
using i64 = long long;

const int N = 5e5 + 10;

template<class T>
struct Fenwick {
    int n;
    vector<T> a;

    Fenwick(int n = 0) {
        init(n);
    }

    void init(int n) {
        this->n = n;
        this->a.assign(n, T());
    }

    void add(int p, T x) {
        for (; p <= n; p += p & -p) {
            a[p] += x;
        }
    }

    int sum(int p) {
        T res = 0;
        for (; p > 0; p -= p & -p) {
            res += a[p];
        }
        return res;
    }
};

vector<vector<int>> pos(N);
vector<int> pt(N), p(N), cnt(N);

void solve() {
    int n, m;
    cin >> n >> m;
    vector<int> a(n + 1);
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        pos[a[i]].emplace_back(i);
        cnt[a[i]] = 1;
    }

    int ans = 0;
    Fenwick<int> fen(n + 1);
    for (int i = 1; i <= n; i++) {
        int mex = a[i];
        int r = i - 1, l;
        if (pos[mex][pt[mex]] == i) {
            l = 0;
        } else {
            l = pos[mex][pt[mex]];
            pt[mex]++;
        }
        cerr << l << ' ' << r << ' ' << fen.sum(r) - fen.sum(l) - mex << '\n';
        ans = max(ans, fen.sum(r) - fen.sum(l) - mex);
        if (p[mex]) {
            fen.add(p[mex], -1);
        }
        fen.add(i, 1);
        p[mex] = i;
    }
    for (int i = 1; i <= n; i++) {
        int mex = a[i];
        int r = n, l = *pos[mex].rbegin();
        cerr << l << ' ' << r << ' ' << fen.sum(r) - fen.sum(l) - mex << '\n';
        ans = max(ans, fen.sum(r) - fen.sum(l) - mex);
    }
    for (int i = 1; i < N; i++) {
        if (!cnt[i]) {
            ans = max(ans, fen.sum(n) - i);
            break;
        }
    }
    cout << ans << '\n';

    for (int i = 1; i <= n; i++) {
        pos[a[i]].clear();
        pt[a[i]] = 0;
        p[a[i]] = 0;
        cnt[a[i]] = 0;
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int t;
    cin >> t;

    while (t--) {
        solve();
    }

    return 0;
}