#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string s) {
    int count=0;
    int digit=0,small=0,capital=0,special=0;
    for(int i=0;i<n;i++){
           if(s[i]>47 && s[i]<58)
               digit++;
        else if(s[i]>64 && s[i]<91)
            capital++;
        else if(s[i]>96 && s[i]<123)
            small++;
        else special++;
    }
    if(digit==0) count++;
    if(capital==0) count++;
    if(small==0) count++;
    if(special==0) count++;
    if((n+count)<6)
        count=count+6-(n+count);
    return count;
        
    // Return the minimum number of characters to make the password strong
}

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