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

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep2(i,s,n) for (int i=(s); i<(int)(n); i++) 
#define all(v) v.begin(),v.end()

using ll=long long;
using vi=vector<int>;
using vvi=vector<vi>;
using vvvi=vector<vvi>;
using vs=vector<string>;
using vl=vector<ll>;
using vvl=vector<vl>;
using vvvl=vector<vvl>;
using vb=vector<bool>;
using vvb=vector<vb>;
using pi=pair<int,int>;
using pl=pair<ll,ll>;
using si=set<int>;
using sl=set<long long>;
using ss=set<string>;
using svi=set<vi>;
using svl=set<vl>;
using svs=set<vs>;
using sb=set<bool>;
using vpi=vector<pi>;
using vpl=vector<pl>;
using spi=set<pi>;
using spl=set<pl>;
const int dx[4]={0,1,0,-1};
const int dy[4]={1,0,-1,0};
template<typename T> using pq=priority_queue<T>;

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

bool isprime(int a){
  for(int i=2;i*i<=a;i++){
    if(a%i==0)return false;
  }
  return true;
}

int main() {
  int a,b;
  cin>>a>>b;
  ll ans=0;
  rep2(i,a,b+1){
    if(isprime(i))ans+=f(i);
  }
  cout<<ans<<endl;
}