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

    let summary: usize = c.iter().map(|i| *i).sum();
    let has2: Vec<usize> = c.iter().map(|i| *i).filter(|&i| i > 1).collect();
    if has2.len() == 0 {
        if summary % 2 == 0 {
            println!("B");
        } else {
            println!("A");
        }
    } else if has2.len() > 1 || has2[0] > 2 {
        println!("B");
    } else {
        if summary % 2 == 0 {
            println!("B");
        } else {
            println!("A");
        }
    }
}