#ifdef NACHIA
#define _GLIBCXX_DEBUG
#else
// disable assert
#define NDEBUG
#endif
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;
using ll = long long;
const ll INF = 1ll << 60;
#define REP(i,n) for(ll i=0; i<ll(n); i++)
template <class T> using V = vector<T>;
template <class A, class B> void chmax(A& l, const B& r){ if(l < r) l = r; }
template <class A, class B> void chmin(A& l, const B& r){ if(r < l) l = r; }


void testcase(){
  ll N; cin >> N;
  string S; cin >> S;
  ll offset = 0;
  REP(i,5) if(S[S.size() - 5 + i] != "HAPPY"[i]) offset++;
  REP(i,5) S[S.size() - 5 + i] = "HAPPY"[i];
  S.pop_back();
  REP(i,S.size()-4) if(S.substr(i,5) == "HAPPY"){ S[i+4] = 'X'; offset++; }
  cout << offset << "\n";
}

int main(){
  cin.tie(0)->sync_with_stdio(0);
  testcase();
  return 0;
}