import java.util.*;

class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		
		int n = sc.nextInt();
		for (int i=1; i<=n; i++) {
			String s = sc.next();
			String t = sc.next();
			if (!s.equals(t) || n==1) {
				System.out.println(i);
				System.out.println(s);
				System.out.println(t);
				return;
			}
		}
		
	}
}