import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String str = sc.nextLine();
		String str1 = "" + str.charAt(0);
		for(int i = 0;i <str.length()-1;i++) {
			if(str.charAt(i) == ' ' && str.charAt(i+1) == ' ') {
				continue;
			}else {
				str1 += str.charAt(i+1);
			}
		}
		String str2 = str1.trim();
		String[] arr = str2.split(" ");
		char f = 'N';
		for(int i = 0 ;i < arr.length - 1;i++) {
			if(arr[i].charAt(arr[i].length()-1) == arr[i+1].charAt(0)
//					&& arr[0].charAt(0) != arr[arr.length-1].charAt(arr[arr.length-1].length()-1
//					)
					)
			{
				f = 'Y';
			}else {
				f = 'N';
				break;
			}
		}
		System.out.println(f);
	}

}
/**************************************************************
	Problem: 1728
	User: admin
	Language: Java
	Result: Accepted
	Time:3261 ms
	Memory:43260 kb
****************************************************************/