use proconio::input; const MD: i64 = 998244353; const HALF: i64 = MD / 2 + 1; fn solve() -> i64 { input! { n: usize, m: usize, } let mu = mu(n.max(m)); let mut ans = 0; for d in 1..n.max(m) { let a = (n / d) as i64; let b = (m / d) as i64; let mut x = mu[d] as i64 * d as i64 * d as i64; x %= MD; x *= a * (a + 1) % MD * HALF % MD; x %= MD; x *= b * (b + 1) % MD * HALF % MD; ans += x; ans %= MD; } ans } fn mu(n: usize) -> Vec { let mut t = vec![1; n + 1]; t[0] = 0; let mut p = vec![true; n + 1]; p[0] = false; p[1] = false; for k in 2..=n { if p[k] { for i in 1.. { let ki = k.saturating_mul(i); if ki > n { break; } p[ki] = false; t[ki] *= -1; let kki = ki.saturating_mul(k); if kki > n { continue; } t[kki] = 0; } } } t } fn main() { let ans = solve(); println!("{}", ans); }