#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string s) {
    // Return the minimum number of characters to make the password strong
    int a=0,b=0,c=0,d=0;
    for(long i=0;i<n;i++)
    {
        if(s[i]>=97 && s[i]<=122)
            a=1;
        if(s[i]>=65 && s[i]<=92)
            b=1;
        if(s[i]>=48 && s[i]<=57)
            c=1;
        if(s[i]=='!' || s[i]=='@' || s[i]=='#' || s[i]=='$' || s[i]=='%' || s[i]=='^' || s[i]=='&' || s[i]=='*' || s[i]=='(' || s[i]==')' || s[i]=='-' || s[i]=='+')
            d=1;
    }
    int count=0;
    if(a!=1)
        count++;
    if(b!=1)
        count++;
    if(c!=1)
        count++;
    if(d!=1)
        count++;
    return max(6-n,count);
}

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