#include <vector> 
#include <list> 
#include <map> 
#include <set> 
#include <deque> 
#include <queue> 
#include <stack> 
#include <bitset> 
#include <algorithm> 
#include <functional> 
#include <numeric> 
#include <utility> 
#include <sstream> 
#include <iostream> 
#include <iomanip> 
#include <cstdio> 
#include <cmath> 
#include <cstdlib> 
#include <cctype> 
#include <string> 
#include <cstring> 
#include <ctime> 

using namespace std;

#define _int64 long long

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

int main()
{
  char s[1000];
  int i,b1,b2,b3,b4,n,ans;
  scanf("%d",&n);
  scanf("%s",s);
  //n=strlen(s);
  b1=0;b2=0;b3=0;b4=0;
  for (i=0;i<n;i++)
  {
    if (numbers.find_first_of(s[i])!=-1) b1=1;
    if (lower_case.find_first_of(s[i])!=-1) b2=1;
    if (upper_case.find_first_of(s[i])!=-1) b3=1;
    if (special_characters.find_first_of(s[i])!=-1) b4=1;
  }
  ans=4-b1-b2-b3-b4;
  if ((n<6)&&(6-n>ans)) ans=6-n;
  printf("%d\n",ans);
  return 0;
}