#include <bits/stdc++.h>
using namespace std;
int main(){
	int H, W; 
	cin >> H >> W; 
	int C[30] = {}; 
	for(int i = 0; i < H * W; i++){
		char c; cin >> c; 
		C[c - 'a'] ++; 
	}
	int res[5] = {}; 
	for(int i = 0; i < 26; i++){
		res[C[i] % 4] ++; 
	}
	string ans = "Yes"; 
	if(H % 2 == 0 && W % 2 == 0){
		if(res[1] || res[2] || res[3]) ans = "No"; 
	}
	else if(H % 2 == 1 && W % 2 == 0){
		if(res[1] || res[3]) ans = "No"; 
		else if(res[2] > W/2) ans = "No"; 
	}
	else if(W % 2 == 1 && H % 2 == 0){
		if(res[1] || res[3]) ans = "No"; 
		else if(res[2] > H/2) ans = "No"; 
	}
	else if(W % 2 == 1 && H % 2 == 1){
		if(res[1] + res[3] != 1) ans = "No"; 
		else if(res[2] + res[3] > (H-1)/2 + (W-1)/2) ans = "No"; 
	}
	cout << ans << endl; 
}