#include <bits/stdc++.h>

using namespace std;
bool occur(char x)
{
    string str = "!@#$%^&*()-+";
    for(int i=0;i<str.size();i++) if(str[i] == x) return 1;
    return 0;
}

int minimumNumber(int n, string password) {
    // Return the minimum number of characters to make the password strong
    int digit=0, lchr=0, uchr=0, spchr=0;
    for(int i=0;i<password.size();i++)
    {
        if(password[i]>=48 &&password[i]<=57 ) {digit = 1; }
        if(password[i]>=65&& password[i]<=90) uchr =1;
        if(password[i]>=97&& password[i]<=122) lchr =1;
        if(occur(password[i])) spchr =1;
    }
    if(4-(digit+lchr+uchr+spchr) + password.size() >=6) return 4-(digit+lchr+uchr+spchr);
    return 6-password.size();
}

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