#include<bits/stdc++.h>
using namespace std;
typedef long double ld;
typedef long long ll;
//#define int ll
#define endl '\n'
#define fi first
#define se second
#define pii pair<int, int>
#define rep(i,a,n,k) for(int i=a;i<=n;i+=k)
#define per(i,a,n,k) for(int i=a;i>=n;i-=k)
/*·········································*/
const int N = 2e7 + 10;
int l, r;
int f[N], tot;
ll ans;
array<ll, 3> ay[N];

int find(int k)
{
	return f[k] == k ? k : f[k] = find(f[k]);
}

void solve()
{
	cin >> l >> r;
	rep(i,l,r,1) f[i] = i;
	rep(i,1,1e5,1)
	{
		ll x = 0;
		rep(j,i,r,i) if(j >= l && j <= r)
		{
			if(!x) x = j;
			else ay[++ tot] = {x / i * j, x, j};
		}
	}
	sort(ay + 1, ay + 1 + tot);
	rep(i,1,tot,1)
	{
		int a = find(ay[i][1]), b = find(ay[i][2]);
		if(a != b)
		{
			ans += ay[i][0];
			f[a] = b;
		}
	}
	cout << ans;
}

signed main()
{
	ios::sync_with_stdio(0);
	cin.tie(0),cout.tie(0);
	int t = 1;
	//cin>>t;
	while(t--) solve();
	return 0;
}