#include<bits/stdc++.h>
using namespace std;
#define int long long 
const int NN=998244353;
int p[100100],ni[100100];
int n;
int mi(int x,int y){
	int sum=1;
	for (;y;y>>=1,x=x*x%NN)
	if(y&1)sum=sum*x%NN;
	return sum;
}
int c(int x,int y){
	if(x<0||y<0||x<y)return 0;
	return p[x]*ni[y]%NN*ni[x-y]%NN;
}
int ans=1;
int f[1010][1010][2];
int a[100100];
signed main(){
	cin>>n;
	int N=1e5;
	p[0]=1;
	for (int i=1;i<=N;i++)
	p[i]=p[i-1]*i%NN;
	ni[N]=mi(p[N],NN-2);
	for (int i=N;i;i--)
	ni[i-1]=ni[i]*i%NN;
	for (int i=1;i<=n;i++)
	cin>>a[i];
	int sum=0;
//	for (int i=0;i<a[1];i++)
//	f[1][i][1]=1;
	f[0][0][1]=1;
	
	for (int i=1;i<=n;i++){
		sum+=a[i];
		
		for (int k=0;k<sum;k++)
		f[i][k][0]=f[i-1][k][0],f[i][k][1]=f[i-1][k][1];
		if(a[i]>=1)
		for (int k=0;k<sum-a[i];k++){
			if(k+1<sum)f[i][k+1][0]=(f[i][k+1][0]+f[i-1][k][1])%NN;
			for (int kk=k+1;kk<sum;kk++)
			f[i][kk][0]=(f[i][kk][0]+f[i-1][k][0]*c(kk-k-1,0))%NN;
			if(1==a[i])continue;
			int kk=sum-(a[i]-1);
			f[i][kk][1]=(f[i][kk][1]+f[i-1][k][0]*c(kk-k-1,0))%NN;
			
		}
		for (int j=2;j<=a[i];j++){
			for (int k=0;k<sum-a[i];k++){
				for (int kk=k+j;kk<sum;kk++){
					f[i][kk][0]=(f[i][kk][0]+f[i-1][k][0]*c(kk-k-1,j-1))%NN;
					f[i][kk][0]=(f[i][kk][0]+f[i-1][k][1]*c(kk-k-2,j-2))%NN;
				}
				if(j==a[i])continue;
				int kk=sum-(a[i]-j);
				f[i][kk][1]=(f[i][kk][1]+f[i-1][k][0]*c(kk-k-1,j-1))%NN;
				f[i][kk][1]=(f[i][kk][1]+f[i-1][k][1]*c(kk-k-2,j-2))%NN;
			}
		}
//		for (int j=0;j<=sum;j++)
//		cout<<f[i][j][0]<<" "<<f[i][j][1]<<" "<<i<<" "<<j<<"\n";
//		cout<<"*******\n";
		for (int j=0;j<sum;j++)
		ans=(ans+f[i][j][0])%NN;
	}
	
	cout<<ans<<"\n";

} //16796