#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define s second
#define f first
#define next tipa_next
#define prev tipa_prev
#define ll long long

using namespace std;
const int mod = 998244353;
const int half = (mod + 1) / 2;
int n , m;
int cnt[26];
string s[100];
int main()
{
	cin >> n >> m;
	for(int i = 0; i < n; i++)
	{
		cin >> s[i];
		for(int j = 0; j < s[i].size(); j++)
			cnt[s[i][j] - 'a']++;
	}
	int x = 0;
	for(int i = 0; i < 26; i++)
		if(cnt[i] % 2)
			x++;
	if(x > 1)
	{
		cout << "No";
		return 0;
	}
	int e = 0;
	for(int i = 0; i < 26; i++)
	{
		if(cnt[i] % 2)
		{
			cnt[i] --;
		}
		e += cnt[i] / 4;
	}
	if(e >= (n / 2) * (m / 2))
		cout << "Yes";
	else
		cout << "No";
}

