#include<bits/stdc++.h>
#define Gc() getchar()
#define Me(x,y) memset(x,y,sizeof(x))
#define Mc(x,y) memcpy(x,y,sizeof(x))
#define d(x,y) ((m)*(x-1)+(y))
#define R(n) (rnd()%(n)+1)
#define Pc(x) putchar(x)
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define eb emplace_back
using namespace std;using ll=long long;using db=double;using lb=long db;using ui=unsigned;using ull=unsigned long long;using pii=pair<int,int>;
const int N=5e5+5,M=N*20+5,K=(1<<25)+5,mod=998244353,Mod=mod-1;const db eps=1e-9;const int INF=1e9+7;mt19937 rnd(time(0));
int n,m,A[N],ns[N],nh,pre[N];vector<int> S[N];
vector<pii> Q[N];
namespace bit{
	int f[N];void clr(){fill(f+1,f+n+1,0);}
	void add(int x,int w){while(x<=n) f[x]+=w,x+=x&-x;}
	int qry(int x){int ans=0;while(x) ans+=f[x],x-=x&-x;return ans;}
}
void Solve(){
	int i,j;scanf("%d%d",&n,&m);
	nh=0;for(i=1;i<=n;i++) scanf("%d",&A[i]),ns[++nh]=A[i];
	sort(ns+1,ns+nh+1);
	for(i=1;i<=m+1;i++){
		auto p=LB(ns+1,ns+nh+1,i)-ns-1;
		if(p>nh||ns[p]^i){ns[++nh]=i;break;}
	}
	sort(ns+1,ns+nh+1);nh=unique(ns+1,ns+nh+1)-ns-1;
	for(i=1;i<=nh;i++) S[i].clear();
	for(i=1;i<=n;i++) A[i]=LB(ns+1,ns+nh+1,A[i])-ns,S[A[i]].emplace_back(i);
	for(i=1;i<=n;i++) Q[i].clear();
	for(i=1;i<=nh;i++){
		S[i].emplace_back(0);S[i].emplace_back(n+1);
		sort(S[i].begin(),S[i].end());
		for(j=1;j<S[i].size();j++) if(S[i][j]-1^S[i][j-1]) Q[S[i][j]-1].emplace_back(S[i][j-1]+1,-ns[i]);
	}
	fill(pre+1,pre+nh+1,0);
	int ans=-INF;bit::clr();
	for(i=1;i<=n;i++){
		if(pre[A[i]]) bit::add(pre[A[i]],-1);
		pre[A[i]]=i;bit::add(i,1);
		for(auto j:Q[i]) ans=max(ans,bit::qry(i)-bit::qry(j.fi-1)+j.se)/*,cerr<<j.fi<<' '<<i<<' '<<bit::qry(i)-bit::qry(j.fi-1)<<'\n'*/;
	}
	printf("%d\n",ans);
}
int main(){
	int t=1;
	scanf("%d",&t);
	while(t--) Solve();
	cerr<<clock()*1.0/CLOCKS_PER_SEC<<'\n';
}