#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int MAXN = 1000005;

int L,R;
int fa[MAXN];

ll ans;
ll val[MAXN];

vector<int> Q[MAXN];
priority_queue<pair<ll,int>,vector<pair<ll,int> >,greater<pair<ll,int> > > S;

int getroot(int u)
{
	return u == fa[u] ? u : fa[u] = getroot(fa[u]);
}

void work(int u)
{
	int tmp = Q[u].back();
	Q[u].pop_back();
	Q[u].pop_back();
	Q[u].push_back(tmp);
	if (Q[u].size() > 1)
	{
		val[u] = (ll)Q[u].back() * Q[u][Q[u].size() - 2] / u;
		S.push(make_pair(val[u],u));
	}
}

int main()
{
	cin >> L >> R;
	for (int i = L;i <= R;i++)
		fa[i] = i;
	for (int i = 1;i <= R;i++)
	{
		int st = ((L - 1) / i + 1) * i;
		for (int j = st;j <= R;j += i)
			Q[i].push_back(j);
		reverse(Q[i].begin(),Q[i].end());
		if (Q[i].size() > 1)
		{
			val[i] = (ll)Q[i].back() * Q[i][Q[i].size() - 2] / i;
			S.push(make_pair(val[i],i));
		}
	}
	while (!S.empty())
	{
		int u = S.top().second;
		S.pop();
		if (getroot(Q[u].back()) == getroot(Q[u][Q[u].size() - 2]))
		{
			work(u);
			continue;
		}
		ans += val[u];
		fa[getroot(Q[u].back())] = getroot(Q[u][Q[u].size() - 2]);
		work(u);
	}
	printf("%lld\n",ans);
	return 0;
}