#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <map>
#include <atcoder/modint>
using namespace std;
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
#define rep(i,n) for(int i=0; i<(int)(n); i++)
const i64 INF = 1001001001001001001;

i64 GCD(i64 a, i64 b){ return b ? GCD(b,a%b) : a; }

using Modint = atcoder::static_modint<1000000007>;


int main(){
    int N; cin >> N;
    vector<int> X(N); rep(i,N) cin >> X[i];
    int sumX = 0;
    for(int x : X) sumX += x;
    Modint Q = 0;
    for(int x : X) Q += Modint(x) * Modint(x-1);
    Q /= Modint(sumX);
    Q = sumX - Q;
    cout << Q.val() << endl;
    return 0;
}



struct ios_do_not_sync{
    ios_do_not_sync(){
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
    }
} ios_do_not_sync_instance;