#!/bin/python3

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    count=0
    num=[]
    lalp=[]
    ualp=[]
    spc=[]
    solution=0
    lf=[num,lalp,ualp,spc]
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    if len(password)>=6:
        for i in range(len(password)):
            if password[i].isupper():
                ualp.append(password[i])
            elif password[i].islower():
                lalp.append(password[i])
            elif (ord(str(password[i]))>=33 and ord(str(password[i]))<=43) or ord(str(password[i])==45):
                spc.append(password[i])
            elif (ord(str(password[i]))>=48 and ord(str(password[i])str)<=57):
                num.append(password[i])
        for i in range(4):
            if len(lf[i])==0:
                count+=1
        count=solution
        print(solution)
    if  len(password)<6:
        for i in range(len(password)):
            if password[i].isupper():
                ualp.append(password[i])
            elif password[i].islower():
                lalp.append(password[i])
            elif (ord(str(password[i]))>=33 and ord(str(password[i]))<=43) or ord(str(password[i])==45):
                spc.append(password[i])
            elif (ord(str(password[i]))>=48 and ord(str(password[i])str)<=57):
                num.append(password[i])
        
        if (len(lf[0])!=0 and len(lf[1])!=0 and len(lf[2])!=0 and len(lf[3])!=0):
            count=6-len(password)
        else:
            for i in range(4):
                if len(lf[i])==0:
                    count+=1
            solution=count+6-(len(password)+count)
        print (solution)
if __name__ == "__main__":
    n = int(input().strip())
    password = input().strip()
    answer = minimumNumber(n, password)
    print(answer)