#nullable enable

var n = int.Parse(Console.ReadLine()!);
var s = Console.ReadLine()!.ToCharArray().AsSpan();
var ans = 0;
var happy = "HAPPY";
for (var i = 1; i <= 5; i++) if (s[^i] != happy[^i]) ans++;
s = s[..(n - 5)];
for (var i = 0; i + 5 <= s.Length; i++)
{
    if (new string(s.Slice(i, 5)) == happy)
    {
        s[i + 4] = 'Z';
        ans++;
    }
}
Console.WriteLine(ans);