#include<bits/stdc++.h>
#define Gc() getchar()
#define Me(x,y) memset(x,y,sizeof(x))
#define Mc(x,y) memcpy(x,y,sizeof(x))
#define d(x,y) ((m)*(x-1)+(y))
#define R(n) (rnd()%(n)+1)
#define Pc(x) putchar(x)
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define eb emplace_back
using namespace std;using ll=long long;using db=double;using lb=long db;using ui=unsigned;using ull=unsigned long long;using pii=pair<int,int>;
const int N=500+5,M=N*10+5,K=1000+5,mod=998244353,Mod=mod-1;const db eps=1e-9;const int INF=1e9+7;mt19937 rnd(263082);
#define Tp template<typename T>
#define Ts template<typename T,typename... Ar>
namespace Debug{
	Tp void _debug(char* f,T t){cerr<<f<<'='<<t<<endl;}
	Ts void _debug(char* f,T x,Ar... y){while(*f!=',') cerr<<*f++;cerr<<'='<<x<<",";_debug(f+1,y...);}
	#ifdef LOCAL
	#define gdb(...) _debug((char*)#__VA_ARGS__,__VA_ARGS__)
	#else 
	#define gdb(...) void()
	#endif
}using namespace Debug;
int n,A[N],m;
ll f[N],g[N],C[N][N];
void Solve(){
	int i,j,h;scanf("%d",&n);
	for(i=1;i<=n;i++) scanf("%d",&A[i]),m+=A[i];
	for(i=0;i<=m;i++) for(C[i][0]=j=1;j<=i;j++) C[i][j]=(C[i-1][j]+C[i-1][j-1])%mod;
	f[0]=1;int sum=0;
	for(i=1;i<=n;i++) if(A[i]){
		Mc(g,f);Me(f,0);
		for(j=0;j<=m;j++) f[j]=g[j];
		for(int k=1;k<=A[i];k++){
			for(j=0;j<=m;j++) {	
				for(h=j+k;h<=sum+k;h++){
					f[h]=(f[h]+g[j]*C[h-j-1][k-1])%mod;
				}
			}
		}
		sum+=A[i];gdb(f[sum]);
	}
	printf("%lld\n",f[m]);
}
int main(){
	int t=1;
	// scanf("%d",&t);
	while(t--) Solve();
	cerr<<clock()*1.0/CLOCKS_PER_SEC<<'\n';
}