#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 fl1,fl2,fl3,fl4;
    fl1=fl2=fl3=fl4=0;
    for(int i=0;i<n;i++)
    {
        if(password[i]>='0'&& password[i]<='9')
            fl1=1;
        if(password[i]>='a' && password[i]<='z')
            fl2=1;
        if(password[i]>='A' && password[i] <='Z')
            fl3=1;
        if(password[i]=='!'|| password[i]=='@' || password[i]=='#' || password[i]=='$' || password[i]=='%' || password[i]=='^'||password[i]=='&'||password[i]=='*'||password[i]=='('||password[i]==')' ||password[i]=='-'||password[i]=='+')
            fl4=1;
    }
    int count=0;
    if(fl1==0)
        count++;
    if(fl2==0)
        count++;
    if(fl3==0)
        count++;
    if(fl4==0)
        count++;
    if(n+count>6)
        return count;
    return 6-(n+count)+count;
}

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