#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string arr) {
    int lower=0,upper=0,number=0,special=0;
    // Return the minimum number of characters to make the password strong
    for(int i=0;i<n;i++)
    {
        if(arr[i] >= 'a' && arr[i] <='z')
            lower=1;
        else if(arr[i]>='A' && arr[i]<='Z')
            upper=1;
        else if(arr[i]>='0' && arr[i] <='9')
            number=1;
        else if(arr[i] == '!' || arr[i]=='@' || arr[i]=='#' || arr[i]=='$' || arr[i]=='%' || arr[i]=='^' || arr[i]=='&' || arr[i]=='*' || arr[i]=='(' || arr[i]==')'|| arr[i]=='-' || arr[i]=='+')
            special=1;            
    }
    int temp=4-(lower+upper+number+special);
    if(n+temp>=6)
        return temp;
    else
        return 6-n;
}

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