#include <bits/stdc++.h>
using namespace std;
int cnt[26], a[4];
char s[1005];
int main() {
	int n, m;
	scanf("%d%d", &n, &m);
	for (int i = 1; i <= n; ++ i) {
		scanf("%s", s + 1);
		for (int j = 1; j <= m; ++ j) {
			cnt[s[j] - 'a'] ++;
		}
	}
	for (int i = 0; i < 26; ++ i) a[cnt[i] % 4] ++;
	if (n % 2 && m % 2) {
		if (a[2] <= n / 2 + m / 2 && a[3] + a[1] == 1) puts("Yes"); else puts("No");
	}
	else if (n % 2 || m % 2) {
		if (n % 2) swap(n, m);
		if (a[1] == 0 && a[3] == 0 && a[2] <= n / 2) puts("Yes"); else puts("No");
	}
	else {
		if (a[1] + a[2] + a[3] == 0) puts("Yes"); else puts("No");
	}
}

