#include <bits/stdc++.h>
#ifndef LOCAL
#define debug(...) 42
#else
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#endif
#define rep1(a) for (int i = 0; i < a; i++)
#define rep2(i, a) for (int i = 0; i < a; i++)
#define rep3(i, a, b) for (int i = a; i < b; i++)
#define rep4(i, a, b, c) for (int i = a; i < b; i += c)
#define overload4(a, b, c, d, e, ...) e
#define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__)

#define pb emplace_back
using namespace std;
template <typename T, typename T2> void cmin(T &x, const T2 &y) {
  x = x < y ? x : y;
}
template <typename T, typename T2> void cmax(T &x, const T2 &y) {
  x = x > y ? x : y;
}
using ll = long long;
using vi = vector<int>;
using pii = pair<int, int>;
template <class T> using vc = vector<T>;
template <class T> using pq = priority_queue<T>;
template <class T> using pqg = priority_queue<T, vector<T>, greater<T>>;
mt19937 rng(time(NULL));
const int inf = 1000000000;
const ll lnf = 1000000000000000000;
#define sz(x) int((x).size())
#define all(x) begin(x), end(x)
#define fi first
#define se second

const int N=5e5+5;
int pos[N];
void solve() {
  int n, m;
  cin >> n >> m;
  vi a(n);
  rep(i,n)cin>>a[i];
  rep(i,n)pos[a[i]]=-1;
  vector<int> t(n*2);
  auto upd=[&](int x,int v){
    x+=n;
    while(x){
      t[x]+=v;
      x/=2;
    }
    return;
  };
  auto query=[&](int l,int r){
    int ans=0;
    for(l+=n,r+=n;l<r;l/=2,r/=2){
      if(l&1)ans+=t[l++];
      if(r&1)ans+=t[--r];
    }
    return ans;
  };
  vc<vc<pii>> querys(n);
  rep(i,n){
    int l=pos[a[i]]+1;
    int r=i-1;
    if(l<=r){
      querys[r].pb(l,-a[i]);
    }
    pos[a[i]]=i;
  }
  rep(i,n){
    int l=pos[a[i]]+1;
    int r=n-1;
    if(l<=r){
      querys[r].pb(l,-a[i]);
    }
  }
  rep(i,n)pos[a[i]]=-1;
  int ans=-1;
  rep(i,n){
    if(pos[a[i]]!=-1)upd(pos[a[i]],-1);
    pos[a[i]]=i,upd(i,1);
    for(auto [j,v]:querys[i])cmax(ans,query(j,i+1)+v);
  }
  cout<<ans<<"\n";
  rep(i,n)pos[a[i]]=-1;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int t = 1;
  cin >> t;
  while (t--) {
    solve();
  }
  return 0;
}