import math
n, m = map(int, input().split())
mod = 998244353
t = (int)(math.sqrt(n))
ans = n * (n + 1) // 2 * m % mod
j = 1
while j < t and j <= m:
    nj = n // j
    ans -= j * nj * (n + 1)
    ans %= mod
    ans += nj * (nj + 1) // 2 * j * j
    ans %= mod
    j += 1
nj, nt = 1, n // t
while nj <= nt:
    l = max(t, (n + nj + 1) // (nj + 1))
    r = min(m, n // nj)
    if l > r:
        nj += 1
        continue
    ll = l * (l - 1) // 2
    rr = r * (r + 1) // 2
    ans -= (n + 1) * nj * (rr - ll)
    ans %= mod
    ans += nj * (nj + 1) * (rr * (2 * r + 1) - ll * (2 * l - 1)) // 6
    ans %= mod
    nj += 1
if ans < 0:
    ans += mod
print(ans)