#include	<bits/stdc++.h>
using	namespace	std;

int	main() {
	int H, W;
	cin >>H >>W;
	vector<int> C(26, 0);
	for (int i=0; i<H*W; i++) {
		char c;
		cin >>c;
		C.at(c-'a')++;
	}
	int HW=(H/2)*(W/2);
	for (int i=0; i<26; i++) {
		int a=min(HW, C.at(i)/4);
		HW -=a;
		C.at(i) -=a*4;
	}
	if (0!=HW) {
		cout <<"No" <<endl;
		return 0;
	}
	HW=(H%2)*(W/2)+(W%2)*(H/2);
	for (int i=0; i<26; i++) {
		int a=min(HW, C.at(i)/2);
		HW -=a;
		C.at(i) -=a*2;
	}
	if (0!=HW) {
		cout <<"No" <<endl;
		return 0;
	}
	cout <<"Yes" <<endl;
	return 0;
};
