def main():

   lst = [5, 9, 18, 25, 27, 34, 99]

   print(lst)

   value =int (input("enter a number ")) 

   ans = binsearch (lst, value, 0, len(lst)-1)

   print(value, "is at", ans)

  

def binsearch (lst, value, left, right):

   print("left", left, "right", right)

   mid = (left + right)//2

   print("mid",mid, lst[mid])

   if right < left:

          ans = -1

   elif lst[mid] == value:

           ans = mid

   elif lst[mid] < value:

        ans = binsearch(lst, value, mid+1, right)

   else:

        ans = binsearch(lst, value, left, mid-1)

   return ans



main()