1 #include<iostream> 2 #include<cstdio> 3 #include<algorithm> 4 #include<vector> 5 #include<cstdlib> 6 #include<cmath> 7 #include<cstring> 8 using namespace std; 9 #define maxn 1001010 #define llg int11 #define md 998244353 12 #define yyj(a) freopen(a".in","r",stdin),freopen(a".out","w",stdout);13 llg n,m,ans,x,w;14 15 inline int getint()16 {17     int w=0;18     char c=getchar();19     while((c<‘0‘ || c>‘9‘) && c!=‘-‘) c=getchar();20     //if (c==‘-‘)  q=1, c=getchar();21     while (c>=‘0‘ && c<=‘9‘) w=w*10+c-‘0‘, c=getchar();22     return w;23 }24 25 int main()26 {27     yyj("a");28     cin>>n;29     for (register llg i=1;i<=n;i++)30     {31         x=getint();32         w+=x;33     }34     ans=1;35     for (register llg i=1;i<=w;i++)  if (i+n!=w+1) ans=1LL*ans*i%md;36     cout<<ans;37     return 0;38 }