#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, t) for (int i = (int)(s); i < (int)(t); ++i)
#define revrep(i, t, s) for (int i = (int)(t)-1; i >= (int)(s); --i)
#define all(x) begin(x), end(x)
template <typename T>
bool chmax(T& a, const T& b) {
    return a < b ? (a = b, 1) : 0;
}
template <typename T>
bool chmin(T& a, const T& b) {
    return a > b ? (a = b, 1) : 0;
}

template <typename M>
class SegmentTree {
    using T = typename M::T;

   public:
    SegmentTree() = default;
    explicit SegmentTree(int n) : SegmentTree(std::vector<T>(n, M::id())) {}
    explicit SegmentTree(const std::vector<T>& v) {
        size = 1;
        while (size < (int)v.size()) size <<= 1;
        node.resize(2 * size, M::id());
        std::copy(v.begin(), v.end(), node.begin() + size);
        for (int i = size - 1; i > 0; --i)
            node[i] = M::op(node[2 * i], node[2 * i + 1]);
    }

    T operator[](int k) const { return node[k + size]; }

    void update(int k, const T& x) {
        k += size;
        node[k] = x;
        while (k >>= 1) node[k] = M::op(node[2 * k], node[2 * k + 1]);
    }

    T fold(int l, int r) const {
        T vl = M::id(), vr = M::id();
        for (l += size, r += size; l < r; l >>= 1, r >>= 1) {
            if (l & 1) vl = M::op(vl, node[l++]);
            if (r & 1) vr = M::op(node[--r], vr);
        }
        return M::op(vl, vr);
    }

    template <typename F>
    int find_first(int l, F cond) const {
        T v = M::id();
        for (l += size; l > 0; l >>= 1) {
            if (l & 1) {
                T nv = M::op(v, node[l]);
                if (cond(nv)) {
                    while (l < size) {
                        nv = M::op(v, node[2 * l]);
                        if (cond(nv))
                            l = 2 * l;
                        else
                            v = nv, l = 2 * l + 1;
                    }
                    return l + 1 - size;
                }
                v = nv;
                ++l;
            }
        }
        return -1;
    }

    template <typename F>
    int find_last(int r, F cond) const {
        T v = M::id();
        for (r += size; r > 0; r >>= 1) {
            if (r & 1) {
                --r;
                T nv = M::op(node[r], v);
                if (cond(nv)) {
                    while (r < size) {
                        nv = M::op(node[2 * r + 1], v);
                        if (cond(nv))
                            r = 2 * r + 1;
                        else
                            v = nv, r = 2 * r;
                    }
                    return r - size;
                }
                v = nv;
            }
        }
        return -1;
    }

   private:
    int size;
    std::vector<T> node;
};

struct MinMonoid {
    using T = int;
    static T id() { return (1u << 31) - 1; }
    static T op(T a, T b) { return min(a, b); }
};

template <typename M>
class FenwickTree {
    using T = typename M::T;

   public:
    FenwickTree() = default;
    explicit FenwickTree(int n) : n(n), data(n + 1, M::id()) {}

    T prefix_fold(int i) const {
        T ret = M::id();
        for (; i > 0; i -= i & -i) ret = M::op(ret, data[i]);
        return ret;
    }

    void update(int i, const T& x) {
        for (++i; i <= n; i += i & -i) data[i] = M::op(data[i], x);
    }

    int lower_bound(const T& x) const { return lower_bound(x, std::less<>()); }

    template <typename Compare>
    int lower_bound(const T& x, Compare cmp) const {
        if (!cmp(M::id(), x)) return 0;
        int k = 1;
        while (k * 2 <= n) k <<= 1;
        int i = 0;
        T v = M::id();
        for (; k > 0; k >>= 1) {
            if (i + k > n) continue;
            T nv = M::op(v, data[i + k]);
            if (cmp(nv, x)) {
                v = nv;
                i += k;
            }
        }
        return i + 1;
    }

   private:
    int n;
    std::vector<T> data;
};

struct AddMonoid {
    using T = int;
    static T id() { return 0; }
    static T op(T a, T b) { return a + b; }
};

template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {
    for (int i = 0; i < (int)v.size(); ++i) {
        os << v[i];
        if (i < (int)v.size() - 1) os << " ";
    }
    return os;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(15);

    const int M = 5e5 + 10;

    vector<int> init(M, -1);
    SegmentTree<MinMonoid> st(init);

    int t;
    cin >> t;
    while (t--) {
        int n, m;
        cin >> n >> m;
        vector<int> a(n);
        for (auto& x : a) cin >> x;

        map<int, int> last;
        FenwickTree<AddMonoid> ft(n);
        int ans = -1;
        rep(i, 0, n) {
            int l = last.count(a[i]) ? last[a[i]] : -1;
            if (l >= 0) {
                ft.update(l, -1);
            }
            ft.update(i, 1);

            int mex = st.find_first(1, [&](int x) { return x <= l; }) - 1;
            if (mex == a[i]) {
                int uniq = ft.prefix_fold(i) - ft.prefix_fold(l + 1);
                chmax(ans, uniq - mex);
            }

            last[a[i]] = i;
            st.update(a[i], i);
        }

        for (auto it : last) {
            int y, l;
            tie(y, l) = it;
            int mex = st.find_first(1, [&](int x) { return x <= l; }) - 1;
            if (mex == y) {
                int uniq = ft.prefix_fold(n) - ft.prefix_fold(l + 1);
                chmax(ans, uniq - mex);
            }
        }

        int mex = st.find_first(1, [&](int x) { return x <= -1; }) - 1;
        int uniq = ft.prefix_fold(n);
        chmax(ans, uniq - mex);

        cout << ans << endl;

        rep(i, 0, n) { st.update(a[i], -1); }
    }
}