import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner sc= new Scanner(System.in);
        int n= sc.nextInt();
        char[] arr= sc.next().toCharArray();
        int upper=0, lower=0,number=0,sp=0;
        int sum=0;
        for (int i = 0; i <n ; i++) {
            if(arr[i]<='z'&&arr[i]>='a'){lower++;}
            else if (arr[i]<='9'&&arr[i]>='0'){number++;}
            else if (arr[i]<='Z'&&arr[i]>='A'){upper++;}
            else{sp++;}
        }
        if(n>=6){
            if(lower==0)sum++;
            if(upper==0)sum++;
            if(number==0)sum++;
            if(sp==0)sum++;
        }
        else{
            if(lower==0)sum++;
            if(upper==0)sum++;
            if(number==0)sum++;
            if(sp==0)sum++;
            if(sum+n<6)sum=(6-n);
        }
        System.out.print(sum);
    }
}