#include using namespace std; //入力が必ず-mod<=a //mod<2^30. struct modint{ //mod変更が不可能. public: int v; static void setmod(int m){} //飾り. static constexpr long long getmod(){return mod;} modint():v(0){} template modint(T a):v(a){if(v < 0) v += mod;} long long val()const{return v;} modint &operator=(const modint &b) = default; modint &operator+()const{return (*this);} modint operator-()const{return modint(0)-(*this);} modint operator+(const modint b)const{return modint(v)+=b;} modint operator-(const modint b)const{return modint(v)-=b;} modint operator*(const modint b)const{return modint(v)*=b;} modint operator/(const modint b)const{return modint(v)/=b;} modint &operator+=(const modint b){ v += b.v; if(v >= mod) v -= mod; return *this; } modint &operator-=(const modint b){ v -= b.v; if(v < 0) v += mod; return *this; } modint &operator*=(const modint b){v = (long long)v*b.v%mod; return *this;} modint &operator/=(modint b){ //b!=0 mod素数が必須. assert(b.v != 0); (*this) *= b.pow(mod-2); return *this; } modint pow(long long n)const{ modint ret = 1,p = v; if(n < 0) p = p.inv(),n = -n; while(n){ if(n&1) ret *= p; p *= p; n >>= 1; } return ret; } modint inv()const{return pow(mod-2);} //素数mod必須. modint &operator++(){*this += 1; return *this;} modint &operator--(){*this -= 1; return *this;} modint operator++(int){modint ret = *this; *this += 1; return ret;} modint operator--(int){modint ret = *this; *this -= 1; return ret;} friend bool operator==(const modint a,const modint b){return a.v==b.v;} friend bool operator!=(const modint a,const modint b){return a.v!=b.v;} friend bool operator<(const modint a,const modint b){return a.v=(const modint a,const modint b){return a.v>=b.v;} friend bool operator>(const modint a,const modint b){return a.v>b.v;} friend ostream &operator<<(ostream &os,const modint a){return os<>(istream &is,modint &a){ //入力はmodをとってくれる. long long x; is >> x; x %= mod; a = modint(x); return is; } }; using mint = modint<998244353>; const long long mod = 998244353; int main(){ ios_base::sync_with_stdio(false); cin.tie(nullptr); int N,M; cin >> N >> M; if(N > M) swap(N,M); int Need = N; vector prime(Need+1); vector allp,lpf(Need+1,1); allp.reserve(1857859); for(int i=2; i<=Need; i++){ if(lpf.at(i) == 1) lpf.at(i) = i,allp.emplace_back(i),prime.at(i) = true; for(auto &p : allp){ if(p*i > Need || p > lpf.at(i)) break; lpf.at(p*i) = p; } } vector F(N+1); F.at(1) = 1; for(int i=2; i<=N; i++){ int k = i/lpf.at(i); if(lpf.at(i) != lpf.at(k)) F.at(i) = -F.at(k); } for(int i=1; i<=N; i++){ F.at(i) *= i,F.at(i) *= i; F.at(i) += F.at(i-1); } mint answer = 0; mint div4 = mint(1)/4; for(int d=1; d<=N; d++){ int n = N/d,m = M/d; mint now = 0,mul = div4*d; int i = 1; while(i <= n){ int m1 = n/i,r1 = n-m1*i; int m2 = m/i,r2 = m-m2*i; int k = min(r1/m1,r2/m2)+i; mint sum = F.at(k)-F.at(i-1); now += sum*m1*(m1+1)*m2*(m2+1); i = k+1; } answer += now*mul; } cout << answer << endl; }