#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define yes cout << "YES\n"
#define no cout << "NO\n";
#define ll long long
#define ull unsigned long long
#define pii pair<int, int>
const int MAX = 5e5 + 10, inf = 2147483647, mod = 998244353;

struct BIT{ //单点更新，区间查询
    int n;
    int sum[MAX];
    int lowbit(int x){
        return x & (-x);
    }
    void init(int n){
        this->n = n;
        for (int i = 0; i <= n; ++ i) sum[i] = 0;
    }
    void update(int pos, ll val){
        for (; pos <= n; pos += lowbit(pos))
            sum[pos] += val;
    }
    int query(int pos){
        ll res = 0;
        for (; pos > 0; pos -= lowbit(pos))
            res += sum[pos];
        return res;
    }
    int query(int l, int r){
        return query(r) - query(l - 1);
    }
};
struct tri{
	int l, r, val;
};
bool cmp(tri a, tri b){
	return a.r < b.r;
}
BIT bit;
void solve(){
	int n, m;
	cin >> n >> m;
	vector<int> a(n + 1);
	for (int i = 1; i <= n; ++ i) cin >> a[i];
	bit.init(n + 1);
	vector<int> last(n + 1);
	vector<tri> range;
	for (int i = 1; i <= n; ++ i){
		if (a[i] > n) continue;
		if (last[a[i]] + 1 != i) range.push_back({last[a[i]] + 1, i - 1, a[i]});
		last[a[i]] = i;
	}
	for (int i = 1; i <= m + 1; ++ i){
		if (last[i] != n or i > n) range.push_back({last[i] + 1, n, i});
		if (last[i] == 0 or i > n) break;
	}
	sort(range.begin(), range.end(), cmp);
	map<int, int> mp;
	int ans = -1e9, cur = 0;
	for (auto [l, r, val]: range){
		while (cur < r){
			cur ++;
			if (mp.count(a[cur])) bit.update(mp[a[cur]], -1);
			mp[a[cur]] = cur;
			bit.update(cur, 1);
		}
		ans = max(ans, bit.query(l, r) - val);
	}
	cout << ans << endl;
}
int main(){
    ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	//cout << fixed << setprecision(6);
	int _;cin>>_;while (_ --)
		solve();
}