#include <bits/stdc++.h>
using namespace std;
bool hh(char c,string s)
{
    for(char x: s) if(x==c) return true;
    return false;
}

int minimumNumber(int n, char* p) {
    // Return the minimum number of characters to make the password strong
    int nm=0,l=0,u=0,s=0;
string numbers = "0123456789";
string lower_case = "abcdefghijklmnopqrstuvwxyz";;
string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";;
string special_characters = "!@#$%^&*()-+";
    for(int i=0;i<n;i++)
    {
        if(hh(p[i],numbers)) nm++;
        if(hh(p[i],lower_case)) l++;
        if(hh(p[i],upper_case)) u++;
        if(hh(p[i],special_characters)) s++;
    }
    int r=0;
    if(!nm) r++;
    if(!l) r++;
    if(!u)r++;
    if(!s) r++;
    return max(6-n,r);
}

int main() {
    int n; 
    scanf("%i", &n);
    char* password = (char *)malloc(512000 * sizeof(char));
    scanf("%s", password);
    int answer = minimumNumber(n, password);
    printf("%d\n", answer);
    return 0;
}