#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
using ll = long long;

ll modpow(ll a, ll b, ll p){
  a%=p;
  ll ans=1;
  while(b>0){
    if(b%2==1) ans=(ans*a)%p;
    b/=2;
    a=(a*a)%p;
  }
  return ans;
}

int main(void){
  ll x; cin >> x;
  vector<ll> y(x);
  ll sum=1, sum2=0, ans=0, mod=998244353, rev=499122177, six=modpow(6, mod-2, mod), ad=0;
  auto f=[&](ll st, ll d, ll num){
    ll last=st+d*(num-1)%mod; last%=mod;
    return num*(st+last)%mod*rev%mod;
  };
  auto g=[&](ll num){
    return num*(num-1)%mod*(num+1)%mod*six%mod;
  };
  for(auto&p:y) cin >> p, sum+=p, sum2+=p*(p+3)%mod*rev%mod, sum2%=mod, sum%=mod;
  for(int i=0; i<x; i++){
    ll base=1+sum2-(y[i]*(y[i]+3)%mod*rev%mod); base=(base+mod)%mod;
    ll d=sum-y[i];
    //cout << i << ' ' << y[i] << ' ' << base << ' ' << d << ' ' << f(base, d, y[i]) << ' ' << y[i]*(y[i]-1)%mod*rev%mod << endl;
    ans+=f(base, d, y[i]); ans%=mod;
    ll ad=g(y[i]); ad%=mod;
    ans+=ad; ans%=mod;
    sum=(sum-y[i]+mod)%mod;
    sum2-=y[i]*(y[i]+3)%mod*rev%mod; sum2=(sum2+mod)%mod;
  }
  cout << ans << endl;
  return 0;
}