#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {

    int lowAlpha = 0 ,upAlpha = 0 ,specialChar = 0 ,digit = 0;
    for(int i = 0 ; i < n ; i++)
    {
        char a = password[i];
        if(a >= '0' && a <= '9')
            digit++;
        else if(a >= 'a' && a <= 'z')
                lowAlpha++;
             else if(a >= 'A' && a <= 'Z')
                        upAlpha++;
                  else if(a == '!' || a == '@' || a == '#' || a == '$' || a == '%' || a == '^' || a=='&' || a=='*' || a=='(' || a==')' || a=='-' || a=='+')
                              specialChar++;
    }
    
    int ans = 0;
    if(digit == 0)
        ans++;
    if(lowAlpha == 0)
        ans++;
    if(upAlpha == 0)
        ans++;
    if(specialChar == 0)
        ans++;
    if((ans + n) < 6)
        ans = 6 - n;
    return ans;
}

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