#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 special = 0, upper = 0, lower = 0, digit = 0;
    for(int i=0; i<n; i++) {
      if(s[i]>='A' && s[i]<='Z') {
        upper++;
      }
      else if(s[i]>='a' && s[i]<='z') {
        lower++;
      }
      else if(s[i]>='0' && s[i]<='9') {
        digit++;
      }
      else {
        special++;
      }
    }
    int need=0; int num = n;
    if(upper==0) {
      need++;
      num++;
    }
    if(lower==0) {
      need++;
      num++;
    }
    if(digit==0) {
      need++;
      num++;
    }
    if(special==0) {
      need++;
      num++;
    }
    //cout<<num<<" "<<need;
    if(num<6) {
      need = 6-num + need;;
    }
    return need;
}

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