#include <bits/stdc++.h>
using namespace std;

int main(void) {
	int A, B;
	cin >> A >> B;
	
	vector<bool> is_prime(B + 1, true);
	is_prime[0] = is_prime[1] = false;
	for(int i = 2; i <= B; ++i) if(is_prime[i]) for(int j = i * 2; j <= B; j += i) is_prime[j] = false;
	
	int ans = 0;
	for(int p = A; p <= B; ++p) if(is_prime[p]) ans += p * p * p - p * p + p + 1;
	
	cout << ans << "\n";
	return 0;
}