use proconio::input;
fn main(){
    input!{
        a:usize,b:usize,
    }
    let mut ans=0;
    for i in (a..b+1){
        if i==1{
            continue;
        }
        let mut s=1;
        for j in (2..i){
            if i%j==0{
                s=0;
            }
        }
        if s==1{
            ans+=i*i*i-i*i+i+1;
        }
    }
    print!("{}",ans);
}