int main(){
char zfc1[500],zfc2[500];
int i,j,t,len1,len2;
double n;
   scanf("%lf",&n);
   scanf("%s %s",zfc1,zfc2);
   len1=strlen(zfc1);
   len2=strlen(zfc2);
   for(i=0;zfc1[i];i++){
   if (len2!=len1||(zfc1[i]!='A'&&zfc1[i]!='T'&&zfc1[i]!='G'&&zfc1[i]!='C')||(zfc2[i]!='A'&&zfc2[i]!='T'&&zfc2[i]!='G'&&zfc2[i]!='C')){
   printf("error");
   return 0;}
   }






	t=0;
	for(j=0;zfc1[j]!='\0';j++){
		if(zfc1[j]==zfc2[j]){
		t++;}
	}
	if(1.0*t/len1>n){
	printf("yes");
	return 0;}
	else {
	printf("no");}

     

      

return 0;


}