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



void solve(){
    vector<bool> p(101, true);
    p[1] = false;
    for(int i = 2; i < 101; ++i){
        if(p[i]){
            for(int j = i * 2; j < 101; j += i){
                p[j] = false;
            }
        }
    }
    int A, B; cin >> A >> B;
    ll ans = 0;
    for(int i = A; i <= B; ++i){
        if(p[i]){
            ans += i * i * i - i * i + i + 1;
        }
    }
    cout << ans << "\n";
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << setprecision(10) << fixed;

    int T;
    T = 1;
    //cin >> T;
    for(;T--;) solve();
}