import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class StrongPassword {

	public static void main(String[] args) throws IOException{
		
		BufferedReader in=new BufferedReader(new InputStreamReader(System.in));
		
		int len=Integer.parseInt(in.readLine());
		char[] string=in.readLine().trim().toCharArray();
		boolean digit=false;
		boolean low=false;
		boolean up=false;
		boolean special=false;
		
		for (int i = 0; i < string.length&&!(digit&&low&&up&&special); i++) {
			if(string[i]>=48&&string[i]<=57) {
				digit=true;
			}else if(string[i]>=97&&string[i]<=122) {
				low=true;
			}else if(string[i]>=65&&string[i]<=90) {
				up=true;
			}else{
				special=true;
			}
			
		}
		int cantidad=0;
		if(!digit)
			cantidad++;
		if(!low)
			cantidad++;
		if(!up)
			cantidad++;
		if(!special)
			cantidad++;
		if(len>=6||len+cantidad>=6) {
			System.out.println(cantidad);
		}else
			System.out.println(6-len);
		
	}

}