Write a function that takes an array of elements and returns only the ints.
returnInts([9, 2, "space", "car", "lion", 16]) ➞ [9, 2, 16]
returnInts(["hello", 81, "basketball", 123, "fox"]) ➞ [81, 123]
returnInts([10, "121", 56, 20, "car", 3, "lion"]) ➞ [10, 56, 20, 3]
returnInts(["String", true, 3.3, 1]) ➞ [1]N/A