#include <iostream>
using namespace std;
int main(void){
    int a[25]={2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97};
    int b,c,sum=0;
    cin>>b>>c;
    for(int i=0;i<25;i++){
        if(a[i]<b)continue;
        if(c<a[i])break;
        sum+=a[i]*a[i]*a[i]-a[i]*a[i]+a[i]+1;
    }
    cout<<sum<<endl;
    return 0;
}