#include<bits/stdc++.h>
#include<atcoder/all>
#define rep(i,b) for(int i=0;i<b;i++)
#define rrep(i,b) for(int i=b-1;i>=0;i--)
#define rep1(i,b) for(int i=1;i<b;i++)
#define repx(i,x,b) for(int i=x;i<b;i++)
#define rrepx(i,x,b) for(int i=b-1;i>=x;i--)
#define fore(i,a) for(auto i:a)
#define fore1(i,a) for(auto &i:a)
#define rng(x) (x).begin(), (x).end()
#define rrng(x) (x).rbegin(), (x).rend()
#define sz(x) ((int)(x).size())
#define pb push_back
#define fi first
#define se second
#define pcnt __builtin_popcountll

using namespace std;
using namespace atcoder;

using ll = long long;
using ld = long double;
template<typename T> using mpq = priority_queue<T, vector<T>, greater<T>>;
template<typename T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<typename T> bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
template<typename T> ll sumv(const vector<T>&a){ll res(0);for(auto&&x:a)res+=x;return res;}
bool yn(bool a) { if(a) {cout << "Yes" << endl; return true;} else {cout << "No" << endl; return false;}}
#define dame { cout << "No" << endl; return;}
#define dame1 { cout << -1 << endl; return;}
#define deb(x,y) cout << x << " " << y << endl;
#define debp(p) cout << p.fi << " " << p.se << endl;
#define out cout << ans << endl;
#define outd cout << fixed << setprecision(20) << ans << endl;
#define outm cout << ans.val() << endl;
#define outv fore(yans , ans) cout << yans << "\n";
#define outdv fore(yans , ans) cout << yans.val() << "\n";
#define coutv(v) {fore(vy , v) {cout << vy << " ";} cout << endl;}
#define countv2(v) fore(vy , v) cout << vy << "\n";
#define coutvm(v) {fore(vy , v) {cout << vy.val() << " ";} cout << endl;}
#define coutvm2(v) fore(vy , v) cout << vy.val() << "\n";
using pll = pair<ll,ll>;using pil = pair<int,ll>;using pli = pair<ll,int>;using pii = pair<int,int>;using pdd = pair<ld,ld>;
using tp = tuple<int ,int ,int>;
using vi = vector<int>;using vd = vector<ld>;using vl = vector<ll>;using vs = vector<string>;using vb = vector<bool>;
using vpii = vector<pii>;using vpli = vector<pli>;using vpll = vector<pll>;using vpil = vector<pil>;
using vvi = vector<vector<int>>;using vvl = vector<vector<ll>>;using vvs = vector<vector<string>>;using vvb = vector<vector<bool>>;
using vvpii = vector<vector<pii>>;using vvpli = vector<vector<pli>>;using vvpll = vector<vpll>;using vvpil = vector<vpil>;
using mint = modint998244353;
using vm = vector<mint>;
using vvm = vector<vector<mint>>;
vector<int> dx={1,0,-1,0,1,1,-1,-1},dy={0,1,0,-1,1,-1,1,-1};
ll gcd(ll a, ll b) { return a?gcd(b%a,a):b;}
ll lcm(ll a, ll b) { return a/gcd(a,b)*b;}
#define yes {cout <<"Yes"<<endl;}
#define yesr { cout <<"Yes"<<endl; return;}
#define no {cout <<"No"<<endl;}
#define nor { cout <<"No"<<endl; return;}
const double eps = 1e-10;
const ll LINF = 1001002003004005006ll;
const int INF = 1001001001;
#ifdef MY_LOCAL_DEBUG
#define show(x) cerr<<#x<<" = "<<x<<endl
#define showp(p) cerr<<#p<<" = "<<p.fi<<" : "<<p.se<<endl
#define show2(x,y) cerr<<#x<<" = "<<x<<" : "<<#y<<" = "<<y<<endl
#define show3(x,y,z) cerr<<#x<<" = "<<x<<" : "<<#y<<" = "<<y<<" : "<<#z<<" = "<<z<<endl
#define show4(x,y,z,x2) cerr<<#x<<" = "<<x<<" : "<<#y<<" = "<<y<<" : "<<#z<<" = "<<z<<" : "<<#x2<<" = "<<x2<<endl
#define test(x) cout << "test" << x << endl
#define showv(v) {fore(vy , v) {cout << vy << " ";} cout << endl;}
#define showv2(v) fore(vy , v) cout << vy << "\n";
#define showvm(v) {fore(vy , v) {cout << vy.val() << " ";} cout << endl;}
#define showvm2(v) fore(vy , v) cout << vy.val() << "\n";
#else
#define show(x)
#define showp(p)
#define show2(x,y)
#define show3(x,y,z)
#define show4(x,y,z,x2)
#define test(x)
#define showv(v)
#define showv2(v)
#define showvm(v)
#define showvm2(v)
#endif

struct math_lib{
    vvl div,mul;

    void div_init(int n){
        div.resize(n+1);
        mul.resize(n+1);

        for(ll i = 1;i <= n;i++){
            for(ll j = i;j <= n;j+=i){
                div[j].pb(i);
                mul[i].pb(j);
            }
        }

        return;
    }

    vl divisor(ll x){
        vl res;
        for(ll i=1;i*i<=x;i++){
            if (x%i != 0) continue;
            res.pb(i);
            if (i*i != x) res.pb(x/i); 
        }
        sort(rng(res));
    
        return res;
    }

    ll sqrt(ll x) {
        ll l = 0, r = ll(2e9)+1;
        while (l+1<r) {
          ll c = (l+r)/2;
          if (c*c <= x) l = c; else r = c;
        }
        return l;
    }

    ll logx(ll x,int a){
        ll tmp=1;
        ll ret=0;

        while(tmp <= x){
            if (tmp >= LLONG_MAX/a) break;
            tmp *= a;
            ret++;
        }
        ret--;

        return ret;
    }

    ll pow(ll x , ll a){

        assert(x > 0);
        assert(a >= 0);

        ll ret = 1;

        rep(_,a){
            assert (ret < LLONG_MAX/x);
            ret *= x;
        }

        return ret;
    }

    ll base(ll x,int a){
        ll ans=0,y;
        for (ll i=0;x>0;i++){
            y = x/a;
            ans += (x - y*a)*pow(10,i);
            x = y;
        }
        return ans;
    }

    string baseS(ll x,int a){
        string ans;
        ll y;
        for (ll i=0;x>0;i++){
            y = x/a;
            ans += '0' + (x - y*a);
            x = y;
        }
        reverse(rng(ans));
        return ans;
    }

    ll inv(vl& v){
        int n = sz(v);
        map<ll,int> mp;
        fore(y,v) mp[y] = 0;
        int m = 0;
        fore1(y,mp) y.se = m++;
        fenwick_tree<ll> fw(m);
        ll ret = 0;
        rep(i,n){
            int k = mp[v[i]];
            ret += fw.sum(k+1,m);
            fw.add(k,1);
        }
        return ret;
    }
} math;

// .div.mul : div[i]、mul[i]はそれぞれiの約数、倍数を格納している。
// .div_init(n) : div,mulを初期化。引数はnまで。n < 1e6 ~ 1e7。
// .divisor(x) : xの約数列挙。xは64bit整数。
// .sqrt(x) : floor(sqrt(x))。xは64bit整数。誤差は発生しない。
// .logx(x , a) : floor(loga(x))。xは64bit整数。誤差は発生しない。
// .pow(x , a) : x^a。誤差は発生しない。
// .base(x , a) : x(10進数)をa進数表記に。1 <= a <= 10。戻り値はll型。 
// .baseS(x , a) : x(10進数)をa進数表記に。1 <= a <= 10。戻り値はstring型。 
// .inv(v) : vの転倒数。 

void solve(){
    ll n,m; cin>>n>>m;
    mint ans = mint(n)*(n+1)/2 * m;

    chmin(m,n);

    mint sum = 0;

    ll c = (ll)sqrt(n);

    ll now = m;
    int nowi = -1;

    vl d;

    ll pre = 0;

    for(int i=1;i*i<=n;i++){
        ll nxt = n/i;
        if (nxt != pre){

        }
    }

    bool ok = false;
    rep1(j,m+1){
        ll k = n/j;
        mint tmp = mint(n+1)*k*j - mint(j)*j*(k*(k+1)/2);
        sum += tmp;

        ll nxt = n / (j+1);
        if (j >= c){
            now = nxt;
            ok = true;
            nowi = j+1;
            break;
        }
    }

    if (ok){
        int l = now;
        rrep(i,l+1){
            ll k = now;
            ll y = nowi;

            ll nxt = i;
            ll ny = n/nxt;

            bool ok2 = false;

            if (ny >= m){
                ny = m;
                ok2 = true;
            }

            mint y1 = (y-1) * y / 2;
            mint y2 = mint(y) * (2*y-1) * (y - 1) / 6;
            mint ny1 = (ny+1) * ny / 2;
            mint ny2 = mint(ny) * (2*ny+1) * (ny + 1) / 6; 

            mint tmp = mint(n+1)*k*(ny1-y1) - mint(k+1)*k/2*(ny2-y2);
            sum += tmp;
            nowi = ny+1;
            now = n / nowi;

            if (ok2){
                break;
            }
        }
    }


    ans -= sum;

    outm;

    return;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);

    int t = 1;
    //cin>>t;

    rep(i,t){
        solve();
    }

    return 0;
}