#include <cstdio>

int main(){
	int h,w,r4,r2,r1,alp[26],matrix[101][101];
	char c;
	for(int i=0;i<26;i++) alp[i]=0;
	scanf("%d %d",&h,&w);
	r4=(h/2)*(w/2);
	r1=(h%2)*(w%2);
	r2=(h*(w%2)+w*(h%2)-2*r1)/2;
	for(int i=0;i<h;i++){
		for(int j=0;j<w;j++){
			scanf("%c",&c);
			while(c==10){
			scanf("%c",&c);
			}
			alp[c-'a']+=1;
		}
	}
	for(int i=0;i<26;i++){
		//printf("%d",alp[i]);
		r4-=alp[i]/4;
		r2-=(alp[i]/2)%2;
		r1-=alp[i]%2;
		//printf("\n%d %d %d\n",r1,r2,r4);
	}
	//printf("\n%d %d %d\n",r1,r2,r4);
	if((r4==0)&&(r2==0)&&(r1==0))
		printf("Yes");
	else if(((w-1)*(h-1))==0&&r1==0)
		printf("Yes");
	else
		printf("No");
	return 0;
}