use std::collections::VecDeque;


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

    if m == 1 {
        println!("{}", n);
        return;
    }
    if n == 1 {
        println!("{}", m);
        return;
    }
    let mut deque = VecDeque::new();
    deque.push_back((3usize, 2usize, 2usize));
    let mut cands = vec![];
    while let Some((summary, cnt, last)) = deque.pop_front() {
        if cnt == n {
            cands.push(summary);
            continue;
        }
        let inserted = last * 2 - 1 > m;
        if last * 2 <= m {
            deque.push_front((summary+last*2, cnt+1, last*2));
        } else if !inserted {
            cands.push(summary + (n - cnt));
        }
        if last * 2 - 1 <= m {
            deque.push_front((summary + last*2-1, cnt+1, last*2-1));
        } else {
            cands.push(summary + (n - cnt));
        }
    }
    println!("{}", cands.iter().max().unwrap());
}