#include<iostream>
using namespace std;
int main(){
  int h,w,four,two,one,i,al[26] = {};char a;cin >> h >> w;bool ok = true;
  while(cin >> a){
    al[int(a)-int('a')] += 1;
  }
  one = (h%2==1)*(w%2==1);
  four = (h/2)*(w/2)*4;
  two = h*w-one-four;
  for(i=0;i<26;i++){
    while(al[i] != 0){
      if(al[i] >= 4 && four > 0){
        four -= 4;
        al[i] -= 4;
      } else if(al[i] >= 2 and two > 0){
        two -= 2;
        al[i] -= 2;
      } else if(al[i] == 1 and one > 0){
        one -= 1;
        al[i] -= 1;
      } else {
        ok = false;break;
      }
    }
  }
  cout << ((ok) ? "Yes":"No") << endl;
}