#include <iostream>

using namespace std;

typedef long long ll;

ll c[11222333];
int a, b;
ll z;

int main() {
    for (int i = 1; i <= 10000000; i++) {
        for (int j = i; j <= 10000000; j += i) {
            c[j] += i;
        }
    }
    cin >> a >> b;
    for (int i = a; i <= b; i++) {
        int u = c[i]-i;
        z += abs(i-u);
    }
    cout << z << "\n";
}