#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    // Return the minimum number of characters to make the password strong
    int k=0,L=0,U=0,N=0,S=0;
string special_characters = "!@#$%^&*()-+";
    string numbers = "0123456789";
string lower_case = "abcdefghijklmnopqrstuvwxyz";
string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    for(int i=0;i<n;i++)
    {
        if(N==0)
        {for(int j=0;j<numbers.length();j++)
            if(password[i]==numbers[j])
            {k++;N=1;break;}}
        if(L==0)
        {for(int j=0;j<lower_case.length();j++)
            if(password[i]==lower_case[j])
            {k++;L=1;break;}}
        if(U==0)
        {for(int j=0;j<upper_case.length();j++)
            if(password[i]==upper_case[j])
            {k++;U=1;break;}}
        if(S==0)
        {for(int j=0;j<special_characters.length();j++)
            if(password[i]==special_characters[j])
            {k++;S=1;break;}}
    }
    //cout<<k<<endl;
    k=4-k;
    if(password.length()>=6)
    return k;
    else 
    {
     if((password.length()+k)>=6)
         return k;
        else
    return k+(6-password.length()-k);
    }
}

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