#include<bits/stdc++.h>
using namespace std;
#define M 1005
#define mod 998244353
#define ll long long
int n,m,x,ans,a[M];
ll qpow(int n,int m){
	ll s=n,ans=1;
	while (m){
		if (m&1)ans=ans*s%mod;
		s=s*s%mod;
		m>>=1;
	}
	return ans;
}
ll g(int x){
	ll s1=1,s2=1,ans1=0,ans2=1;
	for(int i=1;i<=x;i++){
		ans1=(s1*ans2+s2*ans1)%mod;
		ans2=s2*ans2%mod;
		s1=s1*(2*n-i)%mod;
		s2=s2*(n-i)%mod;
	}
	return (mod-2)*ans1%mod*qpow(ans2,mod-2)%mod;
}
int main(){
	scanf("%d",&m);
	for(int i=1;i<=m;i++){
		scanf("%d",&a[i]);
		n+=a[i];
	}
	for(int i=1;i<=m;i++)ans=(ans+g(a[i]))%mod;
	printf("%d",(ans+mod-g(n))%mod);
} 