object Solution {

    val nu = "0123456789".toCharArray.toSet
    val lo = "abcdefghijklmnopqrstuvwxyz"
    val up = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    val sp = "!@#$%^&*()-+".toCharArray.toSet
  
    def minimumNumber(n: Int, p: String): Int =  {
      val arr = p.toCharArray
      val missing = 6 - n
      if(missing >= 4) return missing      
      val digit = arr.exists(x => {
        nu.contains(x)
      })
      val low = arr.exists(x => {
        x >= 'a' && x <= 'z'
      })
      val high = arr.exists(x => {
        x >= 'A' && x <= 'Z'
      })
      val special = arr.exists(x => {
        sp.contains(x)
      })
      //println(s"$digit $low $high $special")
      val bad = Seq(digit, low, high, special).filter(_ == false).size
      Math.max(Math.max(missing, 0), bad)
    }

    def main(args: Array[String]) {
        val sc = new java.util.Scanner (System.in);
        var n = sc.nextInt();
        var password = sc.next();
        val answer = minimumNumber(n, password);
        println(answer)
    }
}