#include <bits/stdc++.h>
// #include <algorithm>
// #include <queue>
// #include <map>
// #include <iostream>
// #include <string>
// #include <set>
#define endl '\n'

using namespace std;

using LL = long long;
using PII = pair<int, int>;
using i128 = __int128_t;
using ULL = unsigned long long;

const int INF = 0x3f3f3f3f, MOD = 1e9 + 7, MAXN = 1e6 + 5;
const LL LINF = 0x3f3f3f3f3f3f3f3f;

int n;
int tr[MAXN];

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

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

int query(int x)
{
    int res = 0;
    for(int i = x; i; i -= lowbit(i)) res += tr[i];

    return res;
}

void solve()
{
    int m;
    cin >> n >> m;
    vector<tuple<int, int, int>> itv;
    vector<int> a(n + 1), pre(n + 2);
    
    for(int i = 1; i <= n; i ++ )
    {
        cin >> a[i];
        if(a[i] > n + 1) continue;
        if(pre[a[i]] + 1 < i)
        {        
            itv.push_back({i - 1, pre[a[i]] + 1, a[i]});
        }
        pre[a[i]] = i;
    }
    
    for(int i = 1; i <= n + 1; i ++ )
    {
        if(pre[i] < n)
            itv.push_back({n, pre[i] + 1, i});
    }
    
    sort(itv.begin(), itv.end());
    
    for(int i = 0; i <= n + 1; i ++ )
        tr[i] = 0, pre[i] = 0;
    
    int sz = itv.size(), ans = 0;
    for(int i = 0, j = 0; i < sz; i ++ )
    {
        auto [r, l, mex] = itv[i];
        while(j < r)
        {
            j ++ ;

            if(a[j] > n + 1) continue;
            if(pre[a[j]])
            {
                add(pre[a[j]], -1);
            }

            add(j, 1);
            pre[a[j]] = j;
        }

        ans = max(ans, query(r) - query(l - 1) - mex);
    }

    cout << ans << endl;
}   

int main()
{
    // freopen("galactic.in", "r", stdin);
    ios::sync_with_stdio(false), cin.tie(nullptr);
    int T = 1; 
    cin >> T;

    while(T -- )
        solve();
    return 0;
}