#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define mp make_pair
#define pb push_back
#define rep(i,n) for(int i=0;i<n;i++)
#define rep1(i,n) for(int i=1;i<=(int)(n);i++)


int main(){
  int h,w;
  cin >> h >> w ;
  string a[h];
  rep(i,h) cin >>a[i];
  int c[26];
  rep(i,26)c[i]=0;
  rep(i,h){
    rep(j,w){
      int ind=a[i][j]-'a';
      c[ind]++;
    }
  }
  int tc=0;
  int oc=0;
  if(h%2==1) tc+=w/2;
  if(w%2==1) tc+=h/2;
  if(h%2==1 && w%2==1) oc=1;

  rep(i,26){
    if(c[i]%4!=0){
      if(c[i]%4==2) tc--;
      if(c[i]%4==1) oc--;
      if(c[i]%4==3){
	tc--;oc--;
      }      
    }
    if(oc<0 || tc<0){
      cout << "No" <<endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
    
  
  return 0;

}
