module Main;

import CPLib.IO;
import CPLib.UnionFind;

main : IO () = (
    let l = *read_i; let r = *read_i;
    let uf = UnionFind::create(r-l+1);
    let uf = range(l, r+1).fold(uf, |x, uf|
        count_up(2).take_while(|i| i*x <= r).map(mul(x)).fold(uf, |y, uf|
            uf.unite(x-l, y-l)
        )
    );
    let ans = uf.get_group_count - 1;
    ans.to_string.println;;
    pure()
);