#include "stdio.h"
#include "string.h"

char s[300000+100];
char h[]="HAPPY";

int main(void){
	int n;
	scanf("%d",&n);
	scanf("%s",s);
	int count=0;
	if(strcmp(&s[n-5],h)==0){
	}else{
		for(int i=0;i<5;i++){
			if(s[n-5+i]!=h[i]){
				count++;
				s[n-5+i]=h[i];
			}
		}
	}
	for(int i=0;i<n;i++){
		char t=s[i+5];
		s[i+5]='\0';
		if(strcmp(&s[i],h)==0){
			count++;
		}
		s[i+5]=t;
	}
	printf("%d\n",count-1);
	return 0;
}