#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define ar array
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
const int maxn = 1e6 + 5, inf = 1e9;
ll solve(int a)
{
ll res = 1ll * a * (a + 1);
for(int d = 1; d <= a; ++d){
res -= 1ll * (a / d) * d;
}
return res;
}
signed main(void)
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#ifdef LOCAL
freopen("A.INP", "r", stdin);
freopen("A.OUT", "w", stdout);
#endif // LOCAL
int a, b; cin >> a >> b;
cout << abs(solve(b) - solve(a - 1));
}
