#include<bits/stdc++.h>
using namespace std;
char s[1005]; int h, w, c[26], cnt1, cnt2;
int main(){
	scanf( "%d%d", &h, &w );
	for( int i = 1; i <= h; i++ ){
		scanf( "%s", s );
		for( int j = 0; j < w; j++ ) c[s[j]-'a']++;
	}
	for( int i = 0; i <  26; i++ ){
		if( c[i] & 1 ) cnt1++;
		c[i] -= c[i]%2;
		if( c[i] % 4 == 2 ) cnt2++;
	}
	int cnt3 = ( h * w ) & 1, cnt4 = h % 2 * (w/2) + w % 2 * (h/2);
	if( cnt1 != cnt3 || cnt2 > cnt4 || ( cnt4 - cnt2 ) % 2 ) puts("No");
	else puts("Yes");
	return 0;
}