fn main() {
    let mut lr = String::new();
    std::io::stdin().read_line(&mut lr).ok();
    let lr: Vec<usize> = lr.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let l = lr[0];
    let r = lr[1];

    let mut sfrees = vec![false; r-l+1];
    let mut vals = (l..=r).collect::<Vec<_>>();
    for i in 2usize..=1000000 {
        let start = l / i * i + if l % i > 0 { i } else { 0 };
        for j in (start..=r).step_by(i) {
            let idx = j - l;
            if sfrees[idx] { continue; }
            if vals[idx] % (i*i) == 0 {
                sfrees[idx] = true;
            } else if vals[idx] % i == 0 {
                vals[idx] = vals[idx] / i;
            }
        }
    }
    let mut result = 0usize;
    for i in l..=r {
        let idx = i - l;
        if sfrees[idx] {
            result += 1;
        } else if vals[idx] > 1 {
            let sqval = (vals[idx] as f64).sqrt().round() as usize;
            if sqval * sqval == vals[idx] {
                result += 1;
            }
        }
    }
    println!("{}", r - l + 1 - result);
}