#include<bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'
#define x first
#define y second
const int N=5e5+5,mod=1e9+7;

int gcd(int a,int b){return b?gcd(b,a%b):a;}
int qmi(int a,int k){
	int res=1;
	while(k){
		if(k&1) res=res*a%mod;
		a=a*a%mod;
		k>>=1;
	}
	return res;
}
typedef pair<int,int> PII;

int a[N];
int n,m;
vector<int> p[N];
vector<PII> val[N]; 
int tr[N];

int lowbit(int x){
    return x & -x;
}

void add(int l,int c){
    for(int i=l;i<=n;i+=lowbit(i)) tr[i]+=c;
}

int sum(int x){
    int res=0;
    for(int i=x;i>=1;i-=lowbit(i)) res+=tr[i];
    return res;
}

void slove(){
	cin>>n>>m;
	for(int i=1;i<=n;i++) cin>>a[i];
	for(int i=1;i<=n;i++) p[i].clear(),val[i].clear();
	for(int i=1;i<=n;i++){
		p[a[i]].push_back(i);
	}
	
	int ans=0;
	for(int i=1;i<=n;i++){//枚举答案 
		if(p[i].size()){//不包含i 
			int len=p[i].size();
			for(int j=0;j<len;j++){
				int l,r;
				if(j==0){
					l=1,r=p[i][j]-1;
					val[r].push_back({l,i});
				}
				else {
					l=p[i][j-1]+1,r=p[i][j]-1;
					val[r].push_back({l,i});
				}
				if(j==len-1){
					l=p[i][j]+1,r=n; 
					val[r].push_back({l,i});
				}
			}	
		}
		else ans=max(ans,n-i);
	}
	map<int,int> ma;
	for(int i=0;i<=n;i++)tr[i]=0;
	
	for(int i=1;i<=n;i++){
		if(ma[a[i]])add(ma[a[i]],-1);
		ma[a[i]]=i;
		add(i,1);
		for(auto zz:val[i]){
			int x=zz.x,y=zz.y;
			ans=max(ans,sum(i)-sum(x-1)-y);
		}
	}
	cout<<ans<<endl;
//2
//5 10000
//5 2 3 4 1
//5 10000
//5 2 3 4 1
}
signed main(){
	ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
	int T=1;
	cin>>T;
	while(T--) slove();
}