#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll=long long;
using ld=long double;
ld pie=3.14159265359;
ll inf=10000000000000001;
ll mod=1000000007;
int main(){
	ll n;
	cin >> n;
	vector<ll>x(n);
	ll sum=0;
	for (ll i = 0; i < n; i++)
	{
		cin >> x[i];
		sum+=x[i];
	}
	ll ans=0;
	for (ll i = 0; i < n; i++)
	{
		ll y=sum-x[i];
		y*=x[i];
		y%=mod;
		ans+=y;
		ans%=mod;
	}
	ans*=inv_mod(sum,mod);
	ans+=1;
	ans%=mod;
	ans%=mod;
	cout << ans << endl;
}