import java.util.Scanner;


public class Main {
	public static void main(String[] a) {
		Scanner s=new Scanner(System.in);
		int i,P,E=1023;
		s.nextInt();
		while(s.hasNext()){
			for(i=0,P=0;i++<4;)P|=(int)Math.pow(2, s.nextInt());
			E&=("NO".equals(s.next())?~P:P)&1023;
		}
		System.out.println((int)(Math.log(E)/Math.log(2)));
	}
}