#include <iostream>
#include <cstdio>
#define int long long
using namespace std;
const int N=5005;
const int mod=998244353;
int ksm(int a,int b){
	int ans=1;
	while(b){
		if(b&1)ans=1ll*ans*a%mod;
		a=1ll*a*a%mod;
		b>>=1;
	}
	return ans;
}
int n,m,a[N],dp[N][N],sum,cnt;
signed main(){
	freopen("hopeicansort.in","r",stdin);
	freopen("hopeicansort.out","w",stdout);
	scanf("%lld %lld",&n,&m);
	for(int i=1;i<=n;i++){
		scanf("%lld",a+i);
		if(a[i]==0)sum++;
	}
	for(int i=1;i<=sum;i++){
		if(a[i]==0)cnt++;
	}
	dp[0][cnt]=1;
	for(int i=0;i<m;i++){
		for(int j=cnt;j<=sum;j++){
			int val1=(sum-j)*(sum-j);
			int val2=n*(n-1)/2-val1;
			(dp[i+1][j]+=dp[i][j]*val2%mod)%=mod;
			(dp[i+1][j+1]+=dp[i][j]*val1%mod)%=mod;
		}
	}
	printf("%lld\n",dp[m][sum]*ksm(ksm((n-1)*n/2,m),mod-2)%mod);
	return 0;
}