#!/bin/python

import sys

def minimumNumber(n, p):
    l=['!','@','#','$','%','^','&','*','(',')','-','+']
    no=['0','1','2','3','4','5','6','7','8','9']
    c=e=f=0
    d=0
    t=0
    for i in range(0,len(password)):
        if(p[i] in l):
            c=1;
        if(p[i] in no):
            e=1
        if(p[i].islower()):
            f=1
        if(p[i].isupper()):
            d=1
        if(f>0 and c>0 and d>0 and e>0):
            t=1
            break
    r=4-(d+c+e+f)
    if(len(p)>6):
        return (r)
    else:
        if(6-len(p)>=r):
            return (6-len(p))
        else:
            return (r)
        
        
    
        

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