Given an array of integers, find the one that appears an odd number of times.

There will always be only one integer that appears an odd number of times.

Examples [7] should return 7, because it occurs 1 time (which is odd). [0] should return 0, because it occurs 1 time (which is odd). [1,1,2] should return 2, because it occurs 1 time (which is odd). [0,1,0,1,0] should return 0, because it occurs 3 times (which is odd). [1,2,2,3,3,3,4,3,3,3,2,2,1] should return 4, because it appears 1 time (which is odd).

• findOdd([20,1,-1,2,-2,3,3,5,5,1,2,4,20,4,-1,-2,5]) should return 5.
• findOdd([1,1,1,1,1,1,10,1,1,1,1]) should return 10.
• findOdd([5,4,3,2,1,5,4,3,2,10,10]) should return 1.

function findOdd(arr) {
  //happy coding!
  return 0;
}