/*
/\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\
/ \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \
/ \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \
*------*------*------*------*------*------*------*------*------*------*------*------*------*------*------*------*------*
\ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ /
\ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ /
\/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/
*/
#include <bits/stdc++.h>
#define fore(i, a, b) for (int i = (a), i##_last = (b); i < i##_last; ++i)
#define fort(i, a, b) for (int i = (a), i##_last = (b); i <= i##_last; ++i)
#define ford(i, a, b) for (int i = (a), i##_last = (b); i >= i##_last; --i)
#define fi first
#define se second
#define pb push_back
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
using namespace std;
using ll = long long;
using ld = long double;
template<class A, class B> bool maxi(A &a, const B &b) {return (a < b) ? (a = b, true):false;};
template<class A, class B> bool mini(A &a, const B &b) {return (a > b) ? (a = b, true):false;};
typedef unsigned long long ull;
typedef pair<int, int> ii;
typedef vector<ll> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
const int maxB = 1e7 + 7;
int a, b;
ll res, sum[maxB];
int ceilint(int x, int y) {
return x / y + !!(x % y);
}
int main() {
#ifdef LOCAL
freopen("input.INP", "r", stdin);
#endif // LOCAL
cin.tie(0) -> sync_with_stdio(0);
cout.tie(0);
cin >> a >> b;
fort(i, 1, b >> 1)
for (int j = max(i << 1, ceilint(a, i) * i); j <= b; j += i)
sum[j] += i;
fort(i, a, b)
res += abs(sum[i] - i);
cout << res << '\n';
return 0;
}
