#[allow(unused)]
use proconio::{input, marker::Chars};

fn main() {
    input! {
        _: usize,
        s: Chars,
    }
    let mut a = vec![0; 26];
    for &c in s.iter() {
        if a[c as usize - 65] > 0 {
            println!("Yes");
            return;
        } else {
            a[c as usize - 65] += 1;
        }
    }
    println!("No")
}