#!/bin/python

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    a="0123456789"
    b="abcdefghijklmnopqrstuvwxyz"
    c="ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    d="!@#$%^&*()-+"
    aa=0
    bb=0
    cc=0
    dd=0
    for i in password:
        if i in a:
            aa=1
        if i in b:
            bb=1
        if i in c:
            cc=1
        if i in d:
            dd=1
    ans=0
    if(aa==0):
        ans+=1
    if(bb==0):
        ans+=1
    if(cc==0):
        ans+=1
    if(dd==0):
        ans+=1
    if(ans==4):
        if(n==0):
            ans=6
        elif(n==1):
            ans=5
    elif(ans==3):
        if(n==1):
            ans=5
        elif(n==2):
            ans=4
    elif(ans==2):
        if(n==2):
            ans=4
        elif(n==3):
            ans=3
    elif(ans==1):
        if(n==3):
            ans=3
        if(n==4):
            ans=2
    elif(ans==0):
        if(n==4):
            ans=2
        if(n==5):
            ans=1
    return ans
        
        

if __name__ == "__main__":
    n = int(raw_input().strip())
    password = raw_input().strip()
    answer = minimumNumber(n, password)
    print answer