#include<bits/stdc++.h>
using namespace std;

int main(){
	int h,w;cin>>h>>w;
	vector<string> a(h);
	for(auto&& w:a)cin>>w;
	map<char,int> cnt;
	string ans="Yes";
	for(int i=0;i<h;i++){
	for(int j=0;j<w;j++){
		cnt[a[i][j]]++;
	}}
	int r1=0,r2=0;
	for(auto&& w:cnt){
	if(w.second%2==1){
		r1++;
	if(w.second%4==3)r2++;
	}
	else if(w.second%4==2)r2++;
	}
	int n0=0;
	if(h%2==1)n0+=w/2;
	if(w%2==1)n0+=h/2;
	if((h%2==1 && w%2==1 && r1>1)|| ((h%2==0 || w%2==0) && r1>0))ans="No";
	if(r2>n0)ans="No";
	cout<<ans<<endl;

}