{-# OPTIONS_GHC -Wno-unused-imports #-}
{-# OPTIONS_GHC -Wno-unused-top-binds #-}
{-# OPTIONS_GHC -Wno-missing-signatures #-}

import Control.Monad
import Control.Monad.State.Strict
import Control.Applicative
import Data.Bool
import Data.Function
import Data.List
import Data.Ord
import Data.List.Split
-- import System.IO (hFlush, stdout)
import Debug.Trace

input = getLine :: IO String
ii = readLn :: IO Int
li = map read . words <$> getLine :: IO [Int]
printYn b = putStrLn $ bool "No" "Yes" b

pairwise :: [a] -> [(a, a)]
pairwise xs = zip xs (drop 1 xs)

windows :: Int -> [a] -> [[a]]
windows size xs
  | length w < size = []
  | otherwise = w : windows size (drop 1 xs)
  where
    w = take size xs

countIf f = length . filter f

minmax (x:xs)
  = foldl' (\(mi, ma) x -> (min mi x, max ma x)) (x, x) xs

solve ('H':'A':'P':'P':'Y':cs) = 1 + solve cs
solve (_:cs) = solve cs
solve [] = 0

main :: IO ()
main = do
  n <- ii
  s <- input
  let (a, b) = splitAt (n-5) s
  let ans = (solve a) + diff b "HAPPY"
  print ans
  where
    diff xs ys = countIf (\(x, y) -> x /= y) $ zip xs ys