n=int(input())
pw=input()
num=['0','1','2','3','4','5','6','7','8','9']
lower_case = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z']
upper_case = ['A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z']
special_characters = ['!','@','#','$','%','^','&','*','(',')','-','+']
need=0
for i in num:
    if(i in pw):
        #number=1
        need+=1
        break
for i in lower_case:
    if(i in pw):
        #lc=1
        need+=1
        break
for i in upper_case:
    if(i in pw):
        #uc=1
        need+=1
        break
for i in special_characters:
    if(i in pw):
        #sc=1
        need+=1
        break
if(n>=6 and need==4):
    print("0")
elif(n>=6 and need!=4):
    print(4-need)
elif(n<6 and need==4):
    print(6-n)
else:
    if((n+(4-need))>=6):
        print(4-need)
    else:
        print((6-(4-need+n))+(4-need))