def binarySearch( arr, l, r, x):
	if r >= l:
		mid = l + ( r-l ) // 2
		

		if arr[mid] == x:
			return mid

		if arr[mid] > x:
			return binarySearch(arr, l, 
								mid - 1, x)

		return binarySearch(arr, mid + 1, r, x)
		
	return -1

def exponentialSearch(arr, n, x):

	if arr[0] == x:
		return 0
		

	i = 1
	while i < n and arr[i] <= x:
		i = i * 2
	
	return binarySearch( arr, i // 2, 
						min(i, n-1), x)
	

arr = list(map(int,input("Enter the array elements: ").split()))
n = len(arr)
x = int(input("enter the number to search: "))
result = exponentialSearch(arr, n, x)
if result == -1:
	print ("Element not found in the array")
else:
	print ("Element is present at index %d" %(result))