#include <bits/stdc++.h>

using i64 = long long;

const int N = 5E5 + 1;
int cnt[N];

void solve() {
    int n, m;
    std::cin >> n >> m;

    std::vector<int> a(n);
    for (int i = 0; i < n; i++) {
        std::cin >> a[i];
    }
    auto b = a;
    std::sort(b.begin(), b.end());
    b.erase(std::unique(b.begin(), b.end()), b.end());

    const int M = b.size();
    int mex = -1;
    for (int i = 0; i < M; i++) {
        if (b[i] != i + 1) {
            mex = i + 1;
            break;
        }
    }
    if (mex == -1) {
        mex = M + 1;
    }

    std::vector<std::vector<int>> pos(mex + 1, {-1});
    for (int i = 0; i < n; i++) {
        if (a[i] < mex) {
            pos[a[i]].emplace_back(i);
        }
    }
    for (int i = 1; i <= mex; i++) {
        pos[i].emplace_back(n);
    }

    std::vector<std::array<int, 3>> qry;
    for (int i = 1; i <= mex; i++) {
        for (int j = 0; j + 1 < pos[i].size(); j++) {
            int l = pos[i][j] + 1, r = pos[i][j + 1] - 1;
            if (l > r) {
                continue;
            }
            qry.push_back({l, r, i});
        }
    }

    const int B = std::ceil(std::sqrt(n));
    std::sort(qry.begin(), qry.end(), [&](auto &lhs, auto &rhs) {
        if (lhs[0] / B != rhs[0] / B) {
            return lhs[0] / B < rhs[0] / B;
        } else if (lhs[1] != rhs[1]) {
            int t = (lhs[0] / B) % 2;
            return t ? lhs[1] < rhs[1] : lhs[1] > rhs[1];
        } else {
            return lhs[2] < rhs[2];
        }
    });

    int res = 0;
    auto add = [&](int x) {
        cnt[x]++;
        if (cnt[x] == 1) {
            res++;
        }
    };

    auto del = [&](int x) {
        cnt[x]--;
        if (cnt[x] == 0) {
            res--;
        }
    };

    int ans = 0;
    int L = 0, R = -1;
    for (auto &[l, r, x] : qry) {
        while (L > l) {
            add(a[--L]);
        }
        while (R < r) {
            add(a[++R]);
        }
        while (L < l) {
            del(a[L++]);
        }
        while (R > r) {
            del(a[R--]);
        }
        ans = std::max(ans, res - x);
    }

    std::cout << ans << "\n";

    for (int i = 0; i < n; i++) {
        cnt[a[i]] = 0;
    }
}

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

    int t;
    std::cin >> t;

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

    return 0;
}