#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
   int count=0;int flag1=0,flag2=0,flag3=0,flag4=0;
    for(int i=0;password[i]!='\0';i++){
        if(flag1==0){
        if((password[i]>=48)&&(password[i]<=57))
        {count++;
            flag1=1;}
    }
        if(flag2==0){
        if((password[i]>=97)&&(password[i]<=122))
        {count++;
            flag2=1;}
    }
     
    if(flag3==0){
        if((password[i]>=65)&&(password[i]<=90))
        {count++;
            flag3=1;}
    }
      if(flag4==0){
        if((password[i]==33)||(password[i]==40)||(password[i]==41)||(password[i]==43)||(password[i]==45)||(password[i]==64)||(password[i]==94)||((password[i]>=35)&&(password[i]<=38)))
        {count++;
            flag4=1;}
    }  
    }
  if((n>=6)&&(count==4)) 
      return 0;
  else if((n<6)&&(count==4)) 
      return 6-n;  
   else if((n<6)&&(count<4)) 
   {
       if((4-count)>(6-n))
           return 4-count;
       else 
           return 6-n;
   }
     else if((n>=6)&&(count<4)) 
   {
           return 4-count;
      
   }
    return 0;
}

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