#define _CRT_SECURE_NO_WARNINGS
#define debug(l) cerr<<#l<<' '<<l<<'\n';
#include "bits/stdc++.h"
using namespace std;
#define all(a) a.begin(), a.end()
typedef long long ll;
typedef pair<ll, ll> pll;
typedef long double ld;
const ll N = 5e6 + 1;
ll O[N], O_pref[N];
constexpr ll BITSIZE = 5e6 + 1;
bitset<BITSIZE> prime;
signed main() {
//#ifdef _DEBUG
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
//#endif
    freopen("lrsigma.in", "r", stdin);
    freopen("lrsigma.out", "w", stdout);
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    prime[0] = 1, prime[1] = 1;
    O[0] = 0;
    O[1] = 1;
    for (ll i = 2; i < N; i++) {
        if (!prime[i]) {
            O[i] = 1 + i;
            for (ll j =  2 * i; j < N; j += i) {
                prime[j] = 1;
                ll sum = 1;
                ll d = j;
                ll pw = 1;
                while (d % i == 0) {
                    d /= i;
                    pw *= i;
                    sum += pw;
                }
                O[j] = O[j / pw] * sum;
            }
        }
    }
    O_pref[0] = 0;
    for (ll i = 1; i < N; i++) {
        O_pref[i] = O_pref[i - 1] + O[i];
    }
    ll l;
    while (cin >> l) {
        ll r;
        cin >> r;
        l--;
        cout << O_pref[r] - O_pref[l] << '\n';
    }
}