#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <string.h>
#include <stdio.h>
using namespace std;

/* 
 * strongify a password
 */


string numbers = "0123456789";
string lower_case = "abcdefghijklmnopqrstuvwxyz";
string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string special_characters = "!@#$%^&*()-+";


int main() {
  int N;
  string inp;
  cin >> N;
  cin >> inp;

  int numNeeded = 0;
  
  // check 6
  if (N < 6)
    numNeeded = 6-N;

  // check digit
  string::iterator it;
  bool bNum = false;
  bool bLow = false;
  bool bUpp = false;
  bool bSpe = false;
  for (it = inp.begin(); it <inp.end(); ++it) {
    char tmpstr = *it;
    if (strchr(numbers.c_str(), tmpstr) != NULL) {
      bNum = true;
    }
    if (strchr(lower_case.c_str(), tmpstr) != NULL) {
      bLow = true;
    }
    if (strchr(upper_case.c_str(),tmpstr) != NULL) {
      bUpp = true;
    }
    if (strchr(special_characters.c_str(),tmpstr) != NULL) {
      bSpe = true;
    }
  }
  int count = 0;
  if (!bNum) count ++;
  if (!bLow) count ++;
  if (!bUpp) count ++;
  if (!bSpe) count ++;


  int maxnum  = max(count, numNeeded);

  cout << maxnum;
  
  return 0;
}