// #include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr ll inf = (1LL << 61);
ll dx[8] = {0, 1, 0, -1, 1, -1, -1, 1};
ll dy[8] = {-1, 0, 1, 0, 1, 1, -1, -1};
#define rep(i, n) for (ll i = 0; i < (ll)(n); ++i)
#define REP(i, init, n) for (ll i = (ll)init; i < (ll)(n); ++i)

ll a[110];
int main() {
  rep(i, 110) a[i] = 1;
  a[0] = a[1] = 0;
  REP(i, 1, 110) {
    if (a[i] == 1) {
      for (ll j = 2 * i; j < 110; j += i) {
        a[j] = 0;
      }
    }
  }
  ll A, b;
  cin >> A >> b;
  ll sum = 0;
  REP(i, A, b + 1) {
    if (a[i]) sum += i * i * i - i * i + i + 1;
  }
  cout << sum << endl;
}