#include <bits/stdc++.h>
typedef long long LL;
#define SORT(c) sort((c).begin(),(c).end())
 
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
 
using namespace std;
int main(void)
{
  int h,w;
  cin >> h >> w;
  string s;
  vector<int> bu(128,0);
  REP(i,h) {
    cin >> s;
    REP(j,w) bu[s[j]]++;
  }
  int buf2=0;
  if(h%2) buf2+= w/2;
  if(w%2) buf2+= h/2;
  int buf1=0;
  if(h%2 && w%2) buf1++;
  for(int co: bu){
    if(co%2) buf1--;
    if((co/2)%2) buf2--;
  }
  bool flag = (buf1>=0) && (buf2>=0);
  cout << (flag ? "Yes" : "No") << endl;
  return 0;
}