urgent (python)

Problem 2. Zero Sum Write a program which prompts the user to enter a list of integers whose end is indicated by the sentinel-999. . Your program is supposed to check whether or not the list contains three consecutive integers whose sum is equal to zero. Examples of such lists are shown below underlining the 3 consecutive integers whose sum is zero: 30 10 -21 11 7 -999 30 10 -107 -999 30 0 20 -10 7 -4 22-999 Below are examples of lists not satisfying such a property: 30 10 12 7 -999 10 -999 0-999 -999 Your program is supposed to give a YES/NO answer only