// author:  jieda
// file:	cpp
//#pragma GCC optimize("O3")
#include<bits/stdc++.h>
using namespace std;
# define fi first
# define se second
# define all(x) x.begin(),x.end()
# define stst stringstream
# define pb push_back
# define pf push_front
# define pp push
# define lowbit(x) (x)&(-x)
# define fa(i,op,n) for (ll i = op; i <= n; i++)
# define fb(j,op,n) for (ll j = op; j >= n; j--)
# define fg(i,op,n) for (ll i = op; i != n; i = ne[i])
int dx[4] = {-1,0,1,0},dy[4] = {0,1,0,-1};
typedef unsigned long long  ull;
typedef long long ll;
typedef pair<ll,ll> Pll;
typedef pair<int,int> PII;
typedef pair<double,double> PDD;
const ll N = 5e5+10,M = 1e5+10,INF = 0x3f3f3f3f,mod = 1e9+7;
const ll MOD = 212370440130137957ll;//hash(hight)
const int base = 131;
const double eps = 1e-3;
const int seed=10086,mo=1e6+7; //hash(lower)
int prime = 233317;
struct qujian{
	int l,r,mex;
};
void solve(){	
	int n,m;cin>>n>>m;
	vector<int> sum(N<<1),a(N),pre(N<<1);
	vector<qujian> st;
	fa(i,1,n){
		cin>>a[i];
	}
	auto update = [&](int x,int k)->void {
		while(x<=n){
			sum[x] += k;
			x+= lowbit(x);
		}
	};
	auto query = [&](int x) ->ll{
		ll res = 0;
		while(x){
			res +=sum[x];
			x -= lowbit(x);
		}
		return res;
	};
	fa(i,1,n){
		if(a[i]+1<=n&&pre[a[i]]+1<i){
			st.pb({pre[a[i]]+1,i-1,a[i]});
		}
		pre[a[i]] = i;
	}
	fa(i,1,n){
		if(pre[a[i]]+1<=n){
			st.pb({pre[a[i]]+1,n,a[i]});
		}
	}
	sort(all(st),[&](qujian x,qujian y){
		return x.r<y.r;
	});
	for(int i = 1;i<=n;i++){
		pre[a[i]] = 0;
	}
	int now = 0;
	ll ans = 0;
	for(int i  = 0;i<n;i++){
		while(now<st[i].r){
			now++;
			if(pre[a[now]]){
				update(now,-1);
			}
			pre[a[now]] = now;
			update(now,1);
			ans = max(ans,query(st[i].r)-query(st[i].l-1)-st[i].mex);
		}
	}
	cout<<ans<<'\n';
	
}	

int main()
{
	ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	int t = 1;
	cin>>t;
	while(t--){
		solve();
	}
	return 0;
}
/**/