#include <bits/stdc++.h>
using namespace std;
#define f first
#define s second
#define int long long
const int N = 5e5 + 69;
int n, m, a[N], lst[N], fenw[N];
vector<int> pos[N];
signed main() {
	ios_base::sync_with_stdio(false);
  cout.tie(nullptr); 
  cin.tie(nullptr);
  //freopen("newbarn.in", "r", stdin);
  //freopen(newbarn.out", "w", stdout);
  int tt = 1;
  cin >> tt;
  while (tt--) {
  	cin >> n >> m;
  	for (int i = 1;i <= max(n, m);i++) {
  		fenw[i] = lst[i] = 0;
  		pos[i].clear();
  	}
  	for (int i = 1;i <= n;i++)
  		cin >> a[i];
  	for (int i = 1;i <= m;i++)
  		pos[i].push_back(0);
  	for (int i = 1;i <= n;i++)
  		pos[a[i]].push_back(i);
  	for (int i = 1;i <= m;i++)
  		pos[i].push_back(n + 1);
  	vector<pair<int, int>> q[n + 1];
  	for (int i = 1;i <= m;i++) {
  		for (int j = 1;j < (int)pos[i].size();j++) {
  			q[pos[i][j] - 1].push_back({pos[i][j - 1] + 1, i});
  		}
  	}
  	auto add = [&](int v, int val) {
  		for (int i = v;i < N;i += (i & -i))
  			fenw[i] += val;
  	};
  	auto get = [&](int v) {
  		int res = 0;
  		for (int i = v;i >= 1;i -= (i & -i))
  			res += fenw[i];
  		return res;
  	};
  	int ans = 0;
  	for (int i = 1;i <= n;i++) {
  		if (lst[a[i]] > 0)
  			add(lst[a[i]], -1);
  		add(i, 1);
  		for (auto u : q[i]) {
  			int l = u.f, mx = u.s;
  			ans = max(ans, get(i) - get(l - 1) - mx);
  		}
  		lst[a[i]] = i;
  	}
  	cout << ans << '\n';
  }
  return 0;
}