// 私は猫です

#include<bits/stdc++.h>
#define ull unsigned long long
#define ll long long
#define pb push_back
#define mkp make_pair
#define fi first
#define se second
#define inf 1000000000
#define infll 1000000000000000000ll
#define pii pair<int,int>
#define rep(i,a,b,c) for(int i=(a);i<=(b);i+=(c))
#define per(i,a,b,c) for(int i=(a);i>=(b);i-=(c))
#define F(i,a,b) for(int i=a,i##end=b;i<=i##end;i++)
#define dF(i,a,b) for(int i=a,i##end=b;i>=i##end;i--)
#define cmh(sjy) while(sjy--)
#define lowbit(x) (x&(-x))
#define HH printf("\n")
#define eb emplace_back
#define poly vector<int>
#define SZ(x) ((int)x.size())
using namespace std;
template<typename T>inline void chkmax(T &x,const T &y){ x=std::max(x,y); }
template<typename T>inline void chkmin(T &x,const T &y){ x=std::min(x,y); }
const int mod=998244353,maxn=150005;
inline int qpow(int x,ll y){ int res=1; for(;y;y>>=1,x=1ll*x*x%mod)if(y&1)res=1ll*res*x%mod; return res; }
inline void inc(int &x,const int y){ x=(x+y>=mod)?(x+y-mod):(x+y); }
inline void dec(int &x,const int y){ x=(x>=y)?(x-y):(x+mod-y); }
inline void mul(int &x,const int y){ x=1ll*x*y%mod; }
inline int add(const int x,const int y){ return (x+y>=mod)?(x+y-mod):(x+y); }
inline int sub(const int x,const int y){ return (x>=y)?(x-y):(x+mod-y); }
inline int prod(const int x,const int y){ return 1ll*x*y%mod; }
mt19937 eng(std::chrono::steady_clock::now().time_since_epoch().count());
inline int rd(const int l,const int r) { return std::uniform_int_distribution<int>(l,r)(eng); }
namespace combi{
	int fac[maxn],ifac[maxn],inv[maxn];
	void init(const int N){
		fac[0]=ifac[0]=inv[0]=1;
		F(i,1,N)fac[i]=1ll*fac[i-1]*i%mod;
		ifac[N]=qpow(fac[N],mod-2);
		dF(i,N-1,1)ifac[i]=1ll*ifac[i+1]*(i+1)%mod;
		F(i,1,N)inv[i]=1ll*ifac[i]*fac[i-1]%mod;
	}
	inline int C(const int n,const int m){
		if(m>n||n<0||m<0) return 0;
		return 1ll*fac[n]*ifac[m]%mod*ifac[n-m]%mod;
	}
}
using namespace combi;
const int NR=505;
int n,m,coef[NR],f[NR][NR],g[NR][NR],dp[NR];
void solve(){
	cin>>n>>m,f[0][0]=g[0][0]=coef[0]=1,init(maxn-3);
	F(_,1,n*m){
		int x; cin>>x;
		dF(i,n-1,0)inc(coef[i+1],1ll*coef[i]*x%mod);
	} const int B=sqrt(n);
	F(i,1,n)F(j,i,n)F(k,1,min(j,B))inc(f[i][j],1ll*f[i-1][j-k]*ifac[k*m-1]%mod);
	F(i,1,n/B)F(j,i,n)F(k,B+1,j)inc(g[i][j],1ll*g[i-1][j-k]*ifac[k*m-1]%mod);
	int ans=0;
	F(k,1,n){
		int res=0;
		F(i,0,min(k,B))F(j,0,n)inc(res,1ll*f[k-i][n-j]*g[i][j]%mod*C(k,i)%mod);
		inc(ans,1ll*res*fac[n*m-k]%mod*coef[k]%mod);
	} cout<<ans;
}
signed main(){
	ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	int zsy=1;
	F(____,1,zsy)solve();
}