#include <bits/stdc++.h>

using namespace std;

int main() {
  int n;
  cin >> n;
  vector <char> v;
  v.push_back('!');
  v.push_back('@');
  v.push_back('#');
  v.push_back('$');
  v.push_back('%');
  v.push_back('^');
  v.push_back('&');
  v.push_back('*');
  v.push_back('(');
  v.push_back(')');
  v.push_back('-');
  v.push_back('+');
  string pass;
  cin >> pass;
  bool low = false;
  bool up = false;
  bool dig = false;
  bool spec = false;
  for (int i=0; i<n; i++) {
    if (pass[i] >= 97 && pass[i] <= 122) {
      low = true;
    } else if (pass[i] >= 65 && pass[i] <= 90) {
      up = true;
    } else if (pass[i] >= 48 && pass[i] <=57) {
      dig = true;
    } else {
      for (int j=0; j<12; j++) {
        if (pass[i] == v[j]) {
          spec = true;
          break;
        }
      }
    }
  }
  int score = 4 - ((int) low + (int) up + (int) dig + (int) spec);
  int kurang = 6 - n;
  if (score > kurang) {
    cout << score << endl;
  } else {
    cout << kurang << endl;
  }
  return 0;
}