#include <iostream>
using namespace std;
bool isPrime(int x) {
    if (x <= 1)
        return false;
    for (int i = 2; i * i <= x; i++) {
        if (x % i == 0)
            return false;
    }
    return true;
}
int main() {
    int A, B;
    cin >> A >> B;   
    long long sum = 0;   
    for (int x = A; x <= B; x++) {
        if (isPrime(x)) {
            long long value = (long long)x * x * x
                              - (long long)x * x
                              + x
                              + 1;
            sum += value;
        }
    }
    cout << sum << endl;
    return 0;
}