#include <stdio.h>
#include <iostream>
#include <math.h>
#include <algorithm>
#include <vector>
using namespace std;

int h, w;
int x[26];
char a;
bool ans = 1;
int flag2 = 0, flag1 = 0;
int tmp;

int main(void) {
  scanf("%d %d",&h, &w);
  for(int i=0;i<26;i++)	x[i] = 0;
  for(int i=0;i<h*w;i++){
    cin>>a;
    x[a-97]++;
  }

  for(int i=0;i<26;i++){
    tmp = x[i] % 4;
    if(tmp >= 2) flag2++;
    if(tmp == 1 || tmp == 3) flag1++;
  }

  if( flag1 != (h*w)%2 ) ans = 0;
  if( flag2 > ( (h%2) * w + (w%2) * h )/2 - ((h*w)%2))	ans = 0;

  if(ans) printf("Yes\n");
  else printf("No\n");

  return 0;
}