#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; using namespace atcoder; typedef long long ll; #define rep(i, n) for (int i = 0; i < (int)(n); i++) #define repr(i, n) for (int i = (int)(n) - 1; i >= 0; i--) #define repk(i, k, n) for (int i = k; i < (int)(n); i++) #define all(v) v.begin(), v.end() #define mod1 1000000007 #define mod2 998244353 #define mod3 100000007 #define vi vector #define vs vector #define vc vector #define vl vector #define vb vector #define vvi vector> #define vvc vector> #define vvl vector> #define vvb vector> #define vvvi vector>> #define vvvl vector>> #define pii pair #define pil pair #define pli pair #define pll pair #define vpii vector> #define vpll vector> #define vvpii vector>> #define vvpll vector>> template void debug(T e) { cerr << e << endl; } template void debug(vector &v) { rep(i, v.size()) { cerr << v[i] << " "; } cerr << endl; } template void debug(vector> &v) { rep(i, v.size()) { rep(j, v[i].size()) { cerr << v[i][j] << " "; } cerr << endl; } } template void debug(vector> &v) { rep(i, v.size()) { cerr << v[i].first << " " << v[i].second << endl; } } template void debug(set &st) { for (auto itr = st.begin(); itr != st.end(); itr++) { cerr << *itr << " "; } cerr << endl; } template void debug(multiset &ms) { for (auto itr = ms.begin(); itr != ms.end(); itr++) { cerr << *itr << " "; } cerr << endl; } template void debug(map &mp) { for (auto itr = mp.begin(); itr != mp.end(); itr++) { cerr << itr->first << " " << itr->second << endl; } } void debug_out() { cerr << endl; } template void debug_out(Head H, Tail... T) { cerr << H << " "; debug_out(T...); } using mint = modint998244353; void debug_mint1(vector &vec) { for (int i = 0; i < vec.size(); i++) { cerr << vec[i].val() << " "; } cerr << endl; } void debug_mint2(vector> &vec) { for (int i = 0; i < vec.size(); i++) { for (int j = 0; j < vec[i].size(); j++) { cerr << vec[i][j].val() << " "; } cerr << endl; } } int main() { ll N, M; cin >> N >> M; // 前問で、\sum (a|x, b|x) μ(x) = 1 であることと、gcd(a, b) = 1 が同値であることを知った // これをもとにした式変形ができればよい? ll L = max(N, M); // mu の和を計算するのに、別の方法はあるか? vector twice(L + 1, false); for (ll i = 2; i * i <= L; i++){ for (ll j = 1; j * i * i <= L; j++){ twice[j * i * i] = true; } } vector isprime(L + 1, true); isprime[0] = false; isprime[1] = false; for (ll i = 2; i <= L; i++){ if (!isprime[i]) continue; for (ll j = 2; j * i <= L; j++){ isprime[i * j] = false; } } vector cnts(L + 1); for (ll i = 2; i <= L; i++){ if (isprime[i]){ for (ll j = 1; j * i <= L; j++){ cnts[i * j]++; } } } vector mu(L + 1, 0); for (ll i = 1; i <= L; i++){ if (!twice[i]){ if (cnts[i] % 2 == 0) mu[i] = 1; else mu[i] = -1; } } mint ans = mint(0); mint inv_4 = mint(1) / mint(4); for (ll d = 1; d <= L; d++){ mint max_n = mint(N / d); mint max_m = mint(M / d); ans += mint(mu[d]) * mint(d) * mint(d) * (max_n * (max_n + 1)) * (max_m * (max_m + 1)) * inv_4; } cout << ans.val() << endl; }