// Author: lycc
//
// NOIp 2024 rp++
// 
// 2024 Grand Master

#include<bits/stdc++.h>
#define int long long
#define lb lower_bound
#define ub upper_bound
#define fi first
#define se second
#define pb emplace_back
#define For(i, x, y) for (int i = (x); i <= (y); i++)
#define rep(i, x, y) for (int i = (x); i >= (y); i--)
#define pii pair<int, int>
#define all(v) v.begin(), v.end()
#define sz(v) (int)(v.size())
#define ull unsigned long long
#define uint unsigned int
#define ls (p << 1)
#define rs (p << 1 | 1)
#define mp make_pair
#define i128 __int128
#define db long double
#define vi vector<int>
using namespace std;
mt19937_64 rnd(time(0));
void cmin(int &x, int y) { x = min(x, y); return; }
void cmax(int &x, int y) { x = max(x, y); return; }
int ksm(int x, int y, int p) {
    int v = 1; x %= p;
    while (y) v = 1ll * v * ((y & 1) ? x : 1) % p, x = 1ll * x * x % p, y >>= 1;
    return (v % p + p) % p;
}
bool MemoryST;
const int N = 1e6 + 30;
const int mod = 998244353;
const long long INF = 1e15;
int n, m, a[N];
int fst[N], nex[N], lst[N], pre[N];
vector< pii > q[N];
int c[N];
void add(int x, int v) {
	if (!x) return;
	while (x <= m) c[x] += v, x += x & -x;
	return;
}
int query(int x) {
	int res = 0;
	while (x) res += c[x], x -= x & -x;
	return res;
}
int query(int x, int y) {
	return query(y) - query(x - 1);
}
void solve() {
	int _, ans = 0;
	cin >> n >> _;
	m = 2 * n + 10;
	int tot = n + 1;
	map< int, int > f;
	For (i, 1, m) pre[i] = nex[i] = lst[i] = fst[i] = 0;
	For (i, 1, n) {
		cin >> a[i];
		if (a[i] >= n + 2) {
			if (f.count(a[i])) a[i] = f[a[i]];
			else f[a[i]] = ++tot, a[i] = tot;
		} 
		if (!fst[a[i]]) fst[a[i]] = i;
		pre[i] = lst[a[i]];
		nex[lst[a[i]]] = i; lst[a[i]] = i;
	}
	For (i, 1, n) q[i].clear();
	For (i, 1, n + 1) {
		if (!fst[i]) q[n].pb(1, i);
		else {
			int now = fst[i];
			if (now != 1) q[now - 1].pb(1, i);
			while (nex[now]) {
				if (now + 1 <= nex[now] - 1) q[nex[now] - 1].pb(now + 1, i);
				now = nex[now];
			}
			if (now < n) q[n].pb(now + 1, i);
		}
	}
	For (i, 1, m) c[i] = 0;
	For (r, 1, n) {
		add(pre[r], -1);
		add(r, 1);
		for (auto [l, i] : q[r]) cmax(ans, query(l, r) - i);
	}
	cout << ans << endl;
    return;
}
bool MemoryED;
signed main() {
    ios::sync_with_stdio(0);
    //cin.tie(0), cout.tie(0);
    //cerr << fixed << setprecision(6) << (&MemoryST - &MemoryED) / 1048576.0 << "MB\n";
    int TESTCNT = 1;
    cin >> TESTCNT;
    while (TESTCNT--) solve();
    //cerr << endl << 1e3 * clock() / CLOCKS_PER_SEC << "ms"; 
    return 0;
}