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

int main(){
    int A, B;
    cin >> A;
    cin >> B;

    int count = 0;
    vector<int> arr;

    if(A <= B){
        int temp = A;
        while(temp <= B){
            for(int i = 2; i < temp; i++){
                if(temp % i == 0){
                    count++;
                    break;
                }
            }

            // minimal fix here
            if(count == 0 && temp >= 2){
                arr.push_back(temp);
            }

            temp++;
            count = 0;
        }

        long long total = 0;
        for(int x : arr){
            total += (1LL * x * x * x) - (1LL * x * x) + x + 1;
        }

        cout << total;
    }

    return 0;
}