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

#define int long long
#define ull unsigned long long
#define vi vector<int>
#define vc vector<char>
#define vs vector<string>
#define vb vector<bool>
#define vpii vector<pair<int, int>>
#define vpic vector<pair<int, char>>
#define vpis vector<pair<int, string>>
#define vvi vector<vector<int>>
#define pb push_back
#define pii pair<int, int>
#define rep(i, s, e) for (int i = (s); i < (e); i++)
#define all(x) x.begin(), x.end()
#define fastio ios::sync_with_stdio(false); cin.tie(0);
#define MOD 1000000007

signed main() {
    fastio
    int a, b;
    cin >> a >> b;
    int ans = 0;
    for(int i=a; i<=b; i++) {
        if(i < 2) continue;
        int temp = i;
        bool prime = true;
        for(int j=2; j*j<=i; j++) {
            if(i%j == 0) {
                prime = false; break;
            }
        }
        if(prime) ans += (i*i*i - i*i + i + 1);
    }
    cout << ans << endl;
}