#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 num=0, lower=0, upper=0, special=0;
    for(char c: password)
    {   if(c>='0' && c<='9')
            num++;
        if(c>='a' && c<='z')
            lower++;
        if(c>='A' && c<='Z')
            upper++;
        if(c=='!' || c=='@' || c=='#' || c=='$' || c=='%' || c=='^' || c=='&' || c=='*' || c=='(' || c==')' || c=='-' || c=='+')
            special++;
    }
    if(n>6)
    {   return !num + !lower + !upper + !special;
    }
    else
    {   return max(6-n, !num + !lower + !upper + !special);        
    }
}

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