#include <atcoder/all>
#include <bits/stdc++.h>
#define rep(i, a, b) for (ll i = (ll)(a); i < (ll)(b); i++)
using namespace atcoder;
using namespace std;

typedef long long ll;

int main() {
    int n, m;
    cin >> n >> m;

    auto f = [&](int x) {
        if (!(1 <= x && x <= n))
            return 0LL;
        ll ret = 0;
        rep(i, 1, m + 1) { ret += x % i; }
        return ret;
    };

    ll ans = 0;
    rep(i, n - 300, n + 1) { ans = max(ans, f(i)); }
    // rep(i, 1, n + 1) { cerr << i << " " << f(i) << endl; }
    cout << ans << endl;
}