#include<cstdio>
#include<algorithm>

using namespace std;

int n, m, two, four;
char s[110];
int num[26];

int main(){
	int t, i, j;
	scanf("%d %d", &n, &m);
	for(i = 1; i <= n; ++i){
		scanf("%s", s + 1);
		for(j = 1; j <= m; ++j)
			++num[s[j]-'a'];
	}
	
	two = (n & 1) * (m / 2) + (m & 1) * (n / 2);
	four = (n / 2) * (m / 2);
	
	for(i = 0; i < 26; ++i){
		t = min(num[i] / 4, four);
		num[i] -= t * 4; four -= t;
	}
	
	for(i = 0; i < 26; ++i){
		t = min(num[i] / 2, two);
		num[i] -= t * 2; two -= t;
	}
	
	if(!four && !two) puts("Yes"); else puts("No");
	return 0;
}