N = int(input())
S = input()
T = "HAPPY"

ans = 0
for i in range(N - 4):
    if i + 5 == N:
        for j in range(5):
            if S[i + j] != T[j]:
                ans += 1
    else:
        if S[i:i + 5] == T:
            ans += 1

print(ans)