#include <bits/stdc++.h>
#include <ctype.h>

using namespace std;

int minimumNumber(int n, string password) {
    bool number = false ;
    bool lower= false;
    bool upper= false;
    bool special= false;
    int total=4;
    for(int i=0;i<n;i++){
        if (isupper(password[i])){
            upper = true;
        }
        if (isupper(password[i])==false && isalpha(password[i])){
            lower = true;
        }
        if (isdigit(password[i])){
            number = true;
        }
        if (ispunct(password[i])){
            special = true;
        }     
    }
    if(upper){
        total--;    
    }
    if(lower){
        total--;    
    }
    if(special){
        total--;    
    }
    if(number){
        total--;    
    }
    if(n<6 && 6-n > total){
        return 6-n;
    }
    return total;
}

int main() {
    int n;
    cin >> n;
    string password;
    cin >> password;
    int answer = minimumNumber(n, password);
    cout << answer << endl;
    return 0;
}