/* Ajay Jadhav */
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <deque>
#include <vector>
#include <cstdlib>
#include <iomanip>
#include <cmath>
#include <queue>
#include <map>
#include <set>
#include <stack>
#include <ctime>
#include <string.h>
#include <climits>
#include <cstring>
using namespace std;
#define ll long long
#define pb push_back
#define pii pair<int, int>
#define vi vector<int>
#define vii vector<pii>
#define mi map<int, int>
#define mii map<pii, int>
#define all(a) (a).begin(), (a).end()
#define x first
#define y second
#define sz(x) (int)x.size()
#define hell 1000000007
#define rep(i, a, b) for (int i = a; i < b; i++)
#define endl '\n'
void solve()
{
int a, b;
cin >> a >> b;
const int N = b + 1;
vector<ll> sum(N + 1);
rep(i, 1, N + 1)
{
sum[i] = i;
}
for (int i = 1; i <= N / 2; i++)
{
for (ll j = 2 * i; j <= N; j += i)
{
sum[j] -= i;
}
}
for (int i = 1; i <= N; i++)
{
sum[i] = abs(sum[i]);
sum[i] += sum[i - 1];
}
cout << sum[b] - sum[a - 1] << endl;
}
signed main()
{
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int t = 1;
// cin>>t;
while (t--)
{
solve();
}
return 0;
}
