#include <stdio.h>

long long power_mod (long long a, long long b, long long mod_num) {
  long long ans = 1LL;
  
  if (b > 0LL) {
    ans = power_mod(a, b/2LL, mod_num);
    ans = (ans * ans) % mod_num;
    if (b%2LL == 1LL) {
      ans = (ans * (a % mod_num)) % mod_num;
    }
  }
  
  return ans;
}

int main () {
  int n = 0;
  long long x = 0LL;
  
  int res = 0;
  
  long long ans = 0LL;
  long long mod_num = 1000000007LL;
  
  long long sum_sq = 0LL;
  
  res = scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    res = scanf("%lld", &x);
    ans += x;
    sum_sq += x*x;
  }
  
  ans = ((ans*ans-sum_sq)%mod_num)*power_mod(ans, mod_num-2LL, mod_num)+1LL;
  
  printf("%lld\n", ans%mod_num);
  return 0;
}