#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;

int f(int x){
    return (x * x * x) - (x * x) + (x) + (1);
}

int main()
{
    int A, B;
    cin >> A >> B;
    int sum = 0;
    for(int i = A; i < B+1; i++){
        bool N = true;
        for(int j = 2; j < i; j++){
            if(i % j == 0){
                N = false;
            }
        }
        if(N){
            sum += f(i);
        }
    }
    cout << sum << endl;
}