#include<bits/stdc++.h>
using namespace std;
using ll=long long;
#define rep(i,n) for(int i=0;i<n;i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
template<class T> bool chmax(T &a, T b){if (a < b){a = b;return true;} else return false;}
template<class T> bool chmin(T &a, T b){if (a > b){a = b;return true;} else return false;}

const ll MOD=998244353;

ll f(ll x){
    return x*(x+1)%MOD*(2*x+1)%MOD*166374059%MOD;
}

ll g(ll x){
    return x*(x+1)/2%MOD;
}

ll n,m;
int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cin>>n>>m;
    ll ans=0;
    ll x=1;
    while(x*x<=n&&x<=m){
        ans+=(x*(x-1)/2%MOD)*(n/x%MOD)%MOD+(n%x)*(n%x+1)/2%MOD;
        ans%=MOD;
        x++;
    }
    ll y=max(1LL,(n+m-1)/m-10);
    bool flag=false;
    while(n/y>=x){
        if(m>=n/y){
            ans+=(y*(y+1)/2)%MOD*(f(n/y)-f(n/(y+1)))%MOD;
            ans%=MOD;
            ans-=(n+1)*y%MOD*(g(n/y)-g(n/(y+1)))%MOD;
            ans%=MOD;
            if(ans<0)ans+=MOD;
            ans+=n*(n+1)/2%MOD*(n/y-n/(y+1))%MOD;
            ans%=MOD;
        }else if(m>n/(y+1)){
            ans+=(y*(y+1)/2)%MOD*(f(m)-f(n/(y+1)))%MOD;
            ans%=MOD;
            ans-=(n+1)*y%MOD*(g(m)-g(n/(y+1)))%MOD;
            ans%=MOD;
            if(ans<0)ans+=MOD;
            ans+=n*(n+1)/2%MOD*(m-n/(y+1))%MOD;
            ans%=MOD;
        }
        y++;
    }
    if(m>n){
        ans+=n*(n+1)/2%MOD*(m-n)%MOD;
    }
    cout<<ans<<endl;
}