Given a positive integer N, how many ways can we write it as a sum of consecutive positive integers? Example 1: Input: 5 Output: 2 Explanation: 5 = 5 = 2 + 3 Example 2: Input: 9 Output: 3 Explanation: 9 = 9 = 4 + 5 = 2 + 3 + 4 Example 3: Input: 15 Output: 4 Explanation: 15 = 15 = 8 + 7 = 4 + 5 + 6 = 1 + 2 + 3 + 4 + 5 Note: 1 <= N <= 10 ^ 9.