import java.util.*;

public class Main {
    public static void main(String[] args){
    
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();    
    int d = sc.nextInt();    
    int e = sc.nextInt();    
    int K = sc.nextInt();    

	if(K>=b-a && K>=c-a && K>=d-a && K>=e-a && K>=c-b && K>=d-b && K>=e-b && K>=d-c && K>=e-c && K>=e-d){
		System.out.println("Yay!");
	}else{
		System.out.println(":(");
	}
	}
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz