#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 dig=0,lc=0,uc=0,sc=0;
    for(int i=0;i<n;i++){
        if(isdigit(password[i]))dig++;
        else if(islower(password[i]))lc++;
         else if(isupper(password[i]))uc++;
        else sc++;
    }
   
   int ans=0;
      if(dig==0)ans++;
        if(lc==0)ans++;
        if(uc==0)ans++;
        if(sc==0)ans++;
    if(ans+n<6)ans+=(6-(ans+n));
    return ans;
}

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