#include<bits/stdc++.h>
// #define int long long
#define pii pair<int, int>
using namespace std;
const int maxn = 5e5 + 10;
const int mod = 998244353;
struct FenTree {
    int len;
    vector<int> t;
    FenTree(int n) { 
        len = n + 2;
        t.resize(len);
    }
    int lowbit(int x) { return x & (-x); }
    void update(int i, int x) {
        for (int pos = i; pos < len; pos += lowbit(pos))
            t[pos] += x;
    }
    int ask(int i) {
        int res = 0;
        for (int pos = i; pos; pos -= lowbit(pos))
            res += t[pos];
        return res;
    }
};
int lst[maxn], arr[maxn];
vector<int> pos[maxn];
vector<pii> query[maxn];
void solve() {
    int n, m;
    cin >> n >> m;
    int up = min(n + 1, m);
    for (int i = 1; i <= up; i++) {
        pos[i].clear();
        pos[i].push_back(0);
    }
    for (int i = 1; i <= n; i++) {
        cin >> arr[i];
        lst[arr[i]] = 0;
        query[i].clear();
        if (arr[i] <= up)
            pos[arr[i]].push_back(i);
    }
    for (int i = 1; i <= up; i++) {
        pos[i].push_back(n + 1);
        for (int j = 1; j < pos[i].size(); j++) {
            int l = pos[i][j - 1] + 1, r = pos[i][j] - 1;
            if (l <= r) {
                query[r].push_back(pii(l, i));
            }
        }
    }
    FenTree tree(n);
    int ans = 0;
    for (int i = 1; i <= n; i++) {
        if (lst[arr[i]] == 0)
            lst[arr[i]] = i, tree.update(i, 1);
        else {
            tree.update(lst[arr[i]], -1);
            lst[arr[i]] = i;
            tree.update(i, 1);
        }
        for (auto [l, c] : query[i]) {
            ans = max(ans, tree.ask(i) - tree.ask(l - 1) - c);
        }
    }
    cout << ans << "\n";
}
signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    int t;
    cin >> t;
    while (t--)
        solve();
    return 0;
}