use proconio::input;

fn main() {
    input! {
        n: usize, m: usize
    }

    let ans = solve(n, m);
    println!("{ans}");
}

fn solve(n: usize, m: usize) -> usize {
    if n % 2 == 0 {
        return n * m;
    }

    let mut less = 0;
    let mut ans = 0;
    for i in (0..30).rev() {
        if m >> i & 1 == 1 {
            ans += (n - 1) << i;
            less = (less + 1).min(n);
        } else {
            ans += (less / 2 * 2) << i;
        }
    }

    ans
}