#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    // Return the minimum number of characters to make the password strong
    long l = password.length();
    int cd=0,cu=0,cl=0,cc=0;
    for(int i=0;i<l;++i)
    {
        if(password[i]>='0'&&password[i]<='9')
            cd++;
        else if(password[i]>='a'&&password[i]<='z')
            cl++;
        else if(password[i]>='A'&&password[i]<='Z')
            cu++;
        else if(password[i]=='!')
            cc++;
        else if(password[i]=='@')
               cc++;
        else if(password[i]=='#')
            cc++;
        else if(password[i]=='$')
            cc++;
        else if(password[i]=='%')
            cc++;
       else if(password[i]=='^')
               cc++;
        else if(password[i]=='&')
                cc++;
        else if(password[i]=='*')
            cc++;
        else if(password[i]=='('||password[i]==')')
            cc++;
        else if(password[i]=='+'||password[i]=='-')
            cc++;
               
    }
    int n_digit=0,n_digit2=0;
    if(cc<1)
        n_digit++;
    if(cu<1)
        n_digit++;
    if(cl<1)
        n_digit++;
    if(cd<1)
        n_digit++;
    if(l<6)
        n_digit2+=6-l;
    return max(n_digit,n_digit2);
}

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