#include<bits/stdc++.h>
#include<atcoder/maxflow>
using namespace atcoder;
using namespace std;
using ll=long long;

int main(){
    ll N,M;
    cin>>N>>M;
    
    ll an=0,id=0;
    for(ll x=1;x<=N;x++){
        ll res=M*x;
        ll d=1;
        while(d<=N){
            ll L=min(x/d,M);
            ll R=x/(d+1);
            if(R<L){
                res-=d*(L*(L+1)/2-R*(R+1)/2);
            }
            if(R==0)break;
            d=x/R;
        }
        an=max(an,res);
    }
    cout<<an<<endl;
}