#include <bits/stdc++.h>
using namespace std;
const int inf = (1 << 30), mod = 1000000007;
const int N = 100005;
long long a, b;
long long binpow(long long x, int pw) {
  long long res = 1;
  while (pw) {
    if (pw & 1) res = res * x % mod;
    x = x * x % mod;
    pw >>= 1;
  }
  return res;
}
int main() {
  scanf("%I64d %I64d\n", &a, &b);
  long long inv2 = binpow(2ll, mod - 2);
  long long ans = a * b % mod * (b - 1) % mod * inv2 % mod *
                  (1 + b * (a + 1) % mod * inv2 % mod) % mod;
  printf("%I64d\n", ans % mod);
  return 0;
}
