#!/bin/python3

import sys

def minimumNumber(n, password):
    s=['!','@','#','$','%','^','&','*','(',')','-','+']
    a=list(password)
    L=[0,0,0,0]
    for i in range(n):
        if a[i].islower()==True:
            L[0]=1
        elif a[i].isupper()==True:
            L[1]=1
        elif a[i].isdigit()==True:
            L[2]=1
        elif a[i] in s:
            L[3]=1
    if n>=6:
        return(L.count(0))
    else:
        return(max(6-len(a),L.count(0)))

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