#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic pop
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;
using mint = modint998244353;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  n++;
  mint ans;
  ans = mint(n) * (n - 1) / 2 * m;
  const mint inv2 = mint(2).inv();
  const mint inv6 = mint(6).inv();
  auto f1 = [&](int x) -> mint {
    return mint(x) * (x - 1) * inv2;
  };
  auto f2 = [&](int x) -> mint {
    //x(x+1)(2x+1)/6
    return mint(x - 1) * (x) * (2 * x - 1) * inv6;
  };
  for(int j = 1; j <= m;) {
    int c = n / j;
    if (c == 0) break;
    int nj = min(n / c, m) + 1;
    mint v = mint(n) * c * (f1(nj) - f1(j));
    v -= f1(c + 1) * (f2(nj) - f2(j));
    ans -= v;
    j = nj;
  }
  cout << ans.val() << '\n';
}