#include <bits/stdc++.h>
#define _rep(i, x, y) for(int i = x; i <= y; ++i)
#define _req(i, x, y) for(int i = x; i >= y; --i)
#define _rev(i, u) for(int i = head[u]; i; i = e[i].nxt)
#define pb push_back
#define fi first
#define se second
#define mst(f, i) memset(f, i, sizeof f)
using namespace std;
#ifdef ONLINE_JUDGE
#define debug(...) 0
#else
#define debug(...) fprintf(stderr, __VA_ARGS__), fflush(stderr)
#endif
typedef long long ll;
typedef pair<int, int> PII;
namespace fastio{
    char ibuf[1 << 20],*p1 = ibuf, *p2 = ibuf;
    #define get() p1 == p2 && (p2 = (p1 = ibuf) + fread(ibuf, 1, 1 << 20, stdin), p1 == p2) ? EOF : *p1++
    template<typename T> inline void read(T &t){
        T x = 0, f = 1;
        char c = getchar();
        while(!isdigit(c)){
            if(c == '-') f = -f;
            c = getchar();
        }
        while(isdigit(c)) x = x * 10 + c - '0', c = getchar();
        t = x * f;
    }
    template<typename T, typename ... Args> inline void read(T &t, Args&... args){
        read(t);
        read(args...);
    }
    template<typename T> void write(T t){
        if(t < 0) putchar('-'), t = -t;
        if(t >= 10) write(t / 10);
        putchar(t % 10 + '0');
    }
    template<typename T, typename ... Args> void write(T t, Args... args){
        write(t), putchar(' '), write(args...);
    }
    template<typename T> void writeln(T t){
        write(t);
        puts("");
    }
    template<typename T> void writes(T t){
        write(t), putchar(' ');
    }
    #undef get
};
using namespace fastio;
#define multitest() int T; read(T); _rep(tCase, 1, T)
namespace Calculation{
    const ll mod = 998244353;
    ll ksm(ll p, ll h){ll base = p % mod, res = 1; while(h){if(h & 1ll) res = res * base % mod; base = base * base % mod, h >>= 1ll;} return res;}
    void dec(ll &x, ll y){x = ((x - y) % mod + mod) % mod;}
    void add(ll &x, ll y){x = (x + y) % mod;}
    void mul(ll &x, ll y){x = x * y % mod;}
    ll sub(ll x, ll y){return ((x - y) % mod + mod) % mod;}
    ll pls(ll x, ll y){return ((x + y) % mod + mod) % mod;}
    ll mult(ll x, ll y){return x * y % mod;}
}
using namespace Calculation;
const int N = 2e5 + 5, _ = 2e5;
int n, m, len, a[N], lsh[N], cnt[N];
ll fac[N], ifac[N];
ll C(ll n, ll m){
    if(n < m || m < 0) return 0;
    if(n == m || !m) return 1;
    return fac[n] * ifac[m] % mod * ifac[n - m] % mod;
}
ll f[N], g[N], h[N];
namespace PolyNomial{
    const int G = 3;
    void pmul(ll *a, ll *b, int n){_rep(i, 0, n) a[i] = 1ll * a[i] * b[i] % mod;}
    void NTT(ll *a, int n){
        static ll f[N << 2], prebuf[N << 2];
        static int tr[N << 2];
        _rep(i, 0, n - 1) tr[i] = (tr[i >> 1] >> 1) | ((i & 1) ? (n >> 1) : 0), f[i] = a[i];
        _rep(i, 0, n - 1) if(i < tr[i]) swap(f[i], f[tr[i]]);
        for(int len = 2; len <= n; len <<= 1){
            int p = len >> 1;
            ll buf = ksm(G, (mod - 1) / len); 
            prebuf[0] = 1; _rep(i, 1, p - 1) prebuf[i] = prebuf[i - 1] * buf % mod;
            for(int k = 0; k < n; k += len){
                _rep(i, 0, p - 1){
                    ll cur = f[i | k | p] % mod * prebuf[i] % mod;
                    f[i | k | p] = f[i | k] + mod - cur;
                    f[i | k] += cur;
                }
            }
        }
        _rep(i, 0, n - 1) a[i] = f[i] % mod, f[i] = 0;
    }
    void INTT(ll *a, int n){
        NTT(a, n), reverse(a + 1, a + n); ll invn = ksm(n, mod - 2);
        _rep(i, 0, n - 1) a[i] = 1ll * a[i] * invn % mod;
    }
    void mul(ll *a, ll *b, int n, int m){
        static ll f[N << 2], g[N << 2]; 
        int lim = 1; for(; lim <= n + m; lim <<= 1);
        _rep(i, 0, n) f[i] = a[i]; _rep(i, 0, m) g[i] = b[i];
        NTT(f, lim), NTT(g, lim), pmul(f, g, lim - 1), INTT(f, lim);
        _rep(i, 0, n + m) a[i] = f[i];
        _rep(i, 0, lim - 1) f[i] = g[i] = 0;
    }
}
int main(){
    fac[0] = ifac[0] = fac[1] = ifac[1] = 1;
    _rep(i, 2, _) fac[i] = fac[i - 1] * i % mod, ifac[i] = (mod - mod / i) * ifac[mod % i] % mod;
    _rep(i, 2, _) ifac[i] = ifac[i - 1] * ifac[i] % mod;
    multitest(){
        read(n, m);
        _rep(i, 1, n * m) read(a[i]), lsh[++len] = a[i];
        sort(lsh + 1, lsh + 1 + len), len = unique(lsh + 1, lsh + 1 + len) - lsh - 1;
        _rep(i, 1, n * m) a[i] = lower_bound(lsh + 1, lsh + 1 + len, a[i]) - lsh, cnt[a[i]]++;
        _rep(i, 1, len) cnt[i] += cnt[i - 1];
        ll ans = 0;
        _rep(i, 0, n) _rep(j, 0, m){
            ll cur = (i + j & 1) ? (mod - 1) : 1, t = i * m + j * n - i * j;
            mul(cur, C(n, i) * C(m, j) % mod * fac[(n - i) * (m - j)] % mod * fac[t] % mod);
            add(f[t], cur * ifac[t] % mod);
        }
        _rep(i, 0, n * m) g[i] = ifac[i];
        PolyNomial::mul(f, g, n * m, n * m);
        _rep(k, 1, len){
            h[k] = f[cnt[k - 1]] * fac[cnt[k - 1]] % mod;
        }
        _rep(i, 1, len) add(ans, (h[i] - h[i + 1] + mod) % mod * lsh[i] % mod);
        writeln(ans);
        _rep(i, 1, len) f[i] = cnt[i] = 0;
        _rep(i, 0, n * m * 2) f[i] = g[i] = h[i] = 0;
        len = 0;
    }
    return 0;
}