#include <bits/stdc++.h>
#define PII pair <int, int>
#define ll long long
#define MP make_pair
#define PB push_back
using namespace std;
constexpr int N = 5e5 + 10;
int T, n, m, a[N], cnt, last[N], Next[N], app[N], fir[N], root[N], ans, mx;
map <int, int> maps;
struct node
{
    int ls, rs, val;
    #define ls(p) t[p].ls
    #define rs(p) t[p].rs
    #define val(p) t[p].val
} t[N << 5];
int update (int p, int l, int r, int pos, int x)
{
    int rt = ++cnt;
    t[rt] = t[p]; val (rt) += x;
    if (l == r) return rt;
    int mid = (l + r) >> 1;
    if (mid >= pos) ls (rt) = update (ls (p), l, mid, pos, x);
    else rs (rt) = update (rs (p), mid + 1, r, pos, x);
    return rt;
}
int query (int p, int l, int r, int pos)
{
    if (l == r) return val (p);
    int mid = (l + r) >> 1;
    if (mid >= pos) return query (ls (p), l, mid, pos) + val (rs (p));
    else return query (rs (p), mid + 1, r, pos);
}
inline void clear ()
{
    ans = -1; cnt = 0;
    maps.clear ();
    for (int i = 1; i <= n; i++) last[i] = 0;
    for (int i = 1; i <= m; i++) fir[i] = app[i] = 0;
}
int main()
{
    ios::sync_with_stdio (false);
    cin.tie (0);
    cout.tie (0);
    cin >> T;
    while (T--)
    {
        clear ();
        cin >> n >> m;
        for (int i = 1; i <= n; i++) {cin >> a[i]; mx = max (mx, a[i]); if (!fir[a[i]]) fir[a[i]] = i;}
        for (int i = n; i >= 1; i--) {Next[i] = maps[a[i]]; maps[a[i]] = i; app[a[i]]++;}
        for (int i = 1; i <= n; i++) {if (!Next[i]) Next[i] = n + 1;}
        for (int i = 1; i <= n; i++)
        {
            if (!last[a[i]]) root[i] = update (root[i - 1], 1, N, i, 1);
            else {root[i] = update (root[i - 1], 1, N, last[a[i]], -1); root[i] = update (root[i], 1, N, i, 1);}
            last[a[i]] = i;
        }
        // cout << query (root[n], 1, N, 1) << "\n";
        // cout << app[1] << "\n";
        for (int i = 1; i <= mx; i++)
        {
            int pos = fir[i];
            // cout << i << " " << pos << " " << Next[pos] << " " << query (root[pos -1], 1, N, 1) - i << "\n";
            if (!app[i]) {ans = max (ans, query (root[n], 1, N, 1) - i); continue;}
            ans = max (ans, query (root[pos - 1], 1, N, 1) - i);
            for (int j = 1; j <= app[i]; j++) {ans = max (ans, query (root[Next[pos] - 1], 1, N, pos + 1) - i); pos = Next[pos];}
        }
        cout << ans << "\n";
    }
    return 0;
}
/*
1
1 1
1
*/