use proconio::input;
fn main() {
    input! {
        a: usize,
        b: usize,
    }
    let mut prime = vec![];
    for i in 2..100 {
        let mut f = true;
        for j in 2..i {
            if i % j == 0 {
                f = false;
                break;
            }
        }
        if f {
            prime.push(i);
        }
    }
    let mut res = 0;
    for x in prime {
        if a <= x && x <= b {
            res += x*x*x - x*x + x + 1;
        }
    }
    println!("{}", res);
}