#include<bits/stdc++.h>
using namespace std;
#define rep(i,N) for(i=0;i<N;i++)
#define ll long long

int main(void){
    ll N,M;

    cin>>N>>M;

    ll ans=0;
    for(ll i=N;N-500<=i&&1<=i;i--){
        ll sum=0;
        for(ll j=1;j<=M;j++)sum+=i%j;
        ans=max(ans,sum);
    }

    cout<<ans<<endl;

    return 0;
}