#![allow(unused_imports, unused_macros, dead_code)]

macro_rules! min {
    (.. $x:expr) => {{
        let mut it = $x.iter();
        it.next().map(|z| it.fold(z, |x, y| min!(x, y)))
    }};
    ($x:expr) => ($x);
    ($x:expr, $($ys:expr),*) => {{
        let t = min!($($ys),*);
        if $x < t { $x } else { t }
    }}
}
macro_rules! max {
    (.. $x:expr) => {{
        let mut it = $x.iter();
        it.next().map(|z| it.fold(z, |x, y| max!(x, y)))
    }};
    ($x:expr) => ($x);
    ($x:expr, $($ys:expr),*) => {{
        let t = max!($($ys),*);
        if $x > t { $x } else { t }
    }}
}
macro_rules! trace {
    ($x:expr) => {
        #[cfg(debug_assertions)]
        eprintln!(">>> {} = {:?}", stringify!($x), $x)
    };
    ($($xs:expr),*) => { trace!(($($xs),*)) }
}
macro_rules! flush {
    () => {
        std::io::stdout().flush().unwrap();
    };
}
macro_rules! put {
    (.. $x:expr) => {{
        let mut it = $x.iter();
        if let Some(x) = it.next() { print!("{}", x); }
        for x in it { print!(" {}", x); }
        println!("");
    }};
    ($x:expr) => { println!("{}", $x) };
    ($x:expr, $($xs:expr),*) => { print!("{} ", $x); put!($($xs),*) }
}

const M: i64 = 1_000_000_007;

fn c2i(c: char) -> usize {
    (c as u8) as usize - ('a' as u8) as usize
}

fn main() {
    let mut sc = Scanner::new();
    let h: usize = sc.cin();
    let w: usize = sc.cin();

    let mut cx = [0; 30];
    for _ in 0..h {
        for c in sc.chars() {
            cx[c2i(c)] += 1;
        }
    }

    let mut by4 = 0;
    let mut by2 = 0;
    let mut by1 = 0;

    for c in 0..30 {
        let mut d = cx[c];
        by4 += (d / 4) * 4;
        d %= 4;
        by2 += (d / 2) * 2;
        d %= 2;
        by1 += d;
    }

    trace!(by4, by2, by1);

    put!(match (h % 2, w % 2) {
        (0, 0) => {
            if by4 == h * w {
                "Yes"
            } else {
                "No"
            }
        }
        (1, 0) => {
            if by4 >= h * w - w && by1 == 0 {
                "Yes"
            } else {
                "No"
            }
        }
        (0, 1) => {
            if by4 >= h * w - h && by1 == 0 {
                "Yes"
            } else {
                "No"
            }
        }
        (1, 1) => {
            if by4 >= (h - 1) * (w - 1) && by1 == 1 {
                "Yes"
            } else {
                "No"
            }
        }
        _ => panic!(),
    });
}

use std::collections::VecDeque;
use std::io::{self, Write};
use std::str::FromStr;

struct Scanner {
    stdin: io::Stdin,
    buffer: VecDeque<String>,
}
impl Scanner {
    fn new() -> Self {
        Scanner {
            stdin: io::stdin(),
            buffer: VecDeque::new(),
        }
    }
    fn cin<T: FromStr>(&mut self) -> T {
        while self.buffer.is_empty() {
            let mut line = String::new();
            let _ = self.stdin.read_line(&mut line);
            for w in line.split_whitespace() {
                self.buffer.push_back(String::from(w));
            }
        }
        self.buffer.pop_front().unwrap().parse::<T>().ok().unwrap()
    }
    fn chars(&mut self) -> Vec<char> {
        self.cin::<String>().chars().collect()
    }
    fn vec<T: FromStr>(&mut self, n: usize) -> Vec<T> {
        (0..n).map(|_| self.cin()).collect()
    }
}


Measured memory_bytes: 2120