#include<bits/stdc++.h>
using namespace std;
const int mod=998244353;
int q[510],dp[510][510],c[510][510],jc[510],f[510],g[510];
int calc(int fi,int m){
	int su=0;
	for(int j=m;j<=fi;j++)(su+=(((j-m)&1)?-1ll:1ll)*c[j-1][m-1]*dp[fi][j]%mod)%=mod;
	return su;
}
int n,m;
int main(){
	//freopen("guide.in","r",stdin);
	//freopen("guide.out","w",stdout); 
	scanf("%d%d",&n,&m);
	c[0][0]=1;
	for(int i=1;i<=n;i++){
		c[i][0]=1;
		for(int j=1;j<=i;j++)c[i][j]=(c[i-1][j-1]+c[i-1][j])%mod;
	}
	bool fl=1;jc[0]=1;
	for(int i=1;i<=n;i++)jc[i]=1ll*i*jc[i-1]%mod,
	scanf("%d",&q[i]),fl&=(q[i]==i);
	dp[0][0]=1;
	for(int i=0;i<n;i++)for(int j=0;j<=i;j++)if(dp[i][j])
	for(int k=i+1;k<=n;k++)
	(dp[k][j+1]+=1ll*dp[i][j]*jc[k-i]%mod)%=mod;
	if(fl){
		int ans=0;
		for(int i=m;i<=n;i++){
			int su=0;
			for(int j=i;j<=n;j++)
			(su+=(((j-i)&1)?-1ll:1ll)*c[j-1][i-1]*dp[n][j]%mod)%=mod;
			(ans+=su)%=mod;
		}
		printf("%d",(ans+mod)%mod);return 0;
	}
	int fi=-1;
	for(int i=1;i<n;i++)if(q[i]>q[i+1]){if(fi==-1)fi=i;break;}
	int ans=calc(fi,m-(n-fi));
	int fr=n;
	for(int i=fi+1;i<n;i++)if(q[i]>q[i+1]){fr=i;break;}
	if(fr-fi>=2&&q[fi]<q[fi+2]){
		for(int i=2;i<=fr-fi;i++)(ans+=1ll*jc[i-1]*calc(fi,m-(n-fi)+i-1)%mod)%=mod;
	}
	return printf("%d",(ans+mod)%mod),0;
}