#include <iostream>
#include <vector>
#include <string>
#include <map>

using namespace std;

int main() {
	int h,w;
	cin >> h >> w;
	map<char,int> cnt;
	for(int i = 0; i < h; i++) {
		string s;
		cin >> s;
		for(char c : s) cnt[c]++;
	}
	int c1 = 0;
	int c2 = 0;
	for(auto x : cnt) {
		if(x.second % 2) c1 ++;
		c2 += x.second / 4 * 4;
	}
	if(c1 != (h*w)%2 || c2 < (h/2*2)*(w/2*2) ) cout << "No" << endl;
	else cout << "Yes" << endl;
	return 0;
}

