#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    int x =0 ;
    int six = 0 ;
    int lowercase =0;
    int uppercase =0;
    int digit =0;
    int special =0;
    for(int i=0;i<n;i++)
    {
        if(isupper(password[i])!=0)
            uppercase++;
        else if(islower(password[i])!=0)
            lowercase++;
        else if(isdigit(password[i])!=0)
            digit++;
        else if(ispunct(password[i])!=0)
            special++;
    }
    if(digit==0)
        x++;
    if(lowercase==0)
        x++;
    if(uppercase==0)
        x++;
    if(special==0)
        x++;
    if(x+n<6)
        x =6-n;
    return x;
}

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