T = "HAPPY"

N = int(input())
S = list(input())

res = 0

for i in range(5):
    if S[i + N - 5] != T[i]:
        res += 1
        S[i + N - 5] = T[i]

for i in range(N - 5):
    if "".join(S[i:i + 5]) == T:
        res += 1
        S[i] = "X"

print(res)