#include <bits/stdc++.h>

using namespace std;
using ll = long long;

constexpr int N = 5e5 + 10;
struct node {
	int l, r, v;
#define ls u << 1
#define rs u << 1 | 1
} tr[N << 2];
void pushup(int u) {
	tr[u].v = tr[ls].v + tr[rs].v;
}
void build(int u, int l, int r) {
	tr[u] = {l, r};
	if(l == r) {
		return ;
	}
	int mid = l + r >> 1;
	build(ls, l, mid), build(rs, mid + 1, r);
	pushup(u);
}
int query(int u, int l, int r) {
	if(tr[u].l >= l && tr[u].r <= r) return tr[u].v;
	int mid = tr[u].l + tr[u].r >> 1;
	int v = 0;
	if(l <= mid) v = v + query(ls, l, r);
	if(r > mid) v = v + query(rs, l, r);
	return v;
}
void modify(int u, int x, int v) {
	if(tr[u].l == x && tr[u].r == x) tr[u].v = v;
	else {
		int mid = tr[u].l + tr[u].r >> 1;
		if(mid >= x) modify(ls, x, v);
		else modify(rs, x, v);
		pushup(u);
	}
}
int n, m, a[N];
void solve() {
	cin >> n >> m;
	vector<vector<int>> g(m + 2);
	for(int i = 1; i <= m + 1; i++) {
		g[i].push_back(0);
	}
	vector<set<int>> s(m + 2);
	for(int i = 1; i <= n; i++) {
		cin >> a[i];
		g[a[i]].push_back(i);
		s[a[i]].insert(i);
	}
	
	build(1, 1, n);
	for(int i = 1; i <= m; i++) {
		if(s[i].empty()) continue;
		auto it = *s[i].begin();
		modify(1, it, 1);
		
		s[i].erase(it);
	}
	for(int i = 1; i <= m + 1; i++) {
		g[i].push_back(n + 1);
	}
	vector<vector<array<int, 2>>> q(n + 2);
	for(int i = 1; i <= m + 1; i++) {
		for(int j = 0; j + 1 < g[i].size(); j++) {
			q[g[i][j] + 1].push_back({g[i][j + 1] - 1, i});
		}
	}
	sort(q.begin(), q.end());
	int ans = -1e9;
	for(int i = 1; i <= n; i++) {
		for(int j = 0; j < q[i].size(); j++) {
			int l = i, r = q[i][j][0], y = q[i][j][1];
			if(l > r) continue;
			int cnt = query(1, l, r);
			ans = max(cnt - y, ans);
			if(!s[a[i]].empty()) {
				auto it = *s[a[i]].begin();
				modify(1, it, 1);
				//cout << it << '\n';
				s[a[i]].erase(it);
			}
		}
		
	}
	cout << ans << '\n';
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	int t;
	t = 1;
	cin >> t;
	while(t--) {
		solve();
	}
	
	return 0;
}