import Data.List
import Control.Monad
import Data.Char

main :: IO ()
main = readLn >>= main'
    where
        main' n = getLine >>= print . solve n

solve :: Int -> String -> Int
solve n xs
    | 6 > n + c = 6 - n
    | otherwise = c
    where
        c = length $ filter (== 0) [d, l, u, s]
        (d, l, u, s) = foldl' ff (0, 0, 0, 0) xs
        ff (w, x, y, z) v
            | isDigit v = (w + 1, x, y, z)
            | isAsciiLower v = (w, x + 1, y, z)
            | isAsciiUpper v = (w, x, y + 1, z)
            | otherwise = (w, x, y, z + 1)