#include <bits/stdc++.h>

using namespace std;

int cnt[27];
int one = 0, two = 0;
char buf[210];
bool cmp(int a, int b){return a>b;}

bool check(){
	for(int i=0;i<26;i++){
		cnt[i] %= 4;
		if(cnt[i] % 2 == 1){
			if(one == 0) return false;
			else one--, cnt[i]--;
		}
		if(cnt[i] == 2){
			if(two == 0) return false;
			else two--, cnt[i]-=2;
		}
	}
	return true;
}
int main(){
	int H,W;
	cin >> H >> W;
	for(int i=0;i<H;i++){
		scanf("%s", buf);
		for(int j=0;j<W;j++){
			cnt[buf[j] - 'a'] ++;
		}
	}
	if(H % 2 == 1 && W % 2 == 1) one = 1;
	if(H % 2 == 1) two += W/2;
	if(W % 2 == 1) two += H/2;
	if(check()) puts("Yes");
	else puts("No");
}
