Given four integers n, a, b, and c, return the nth ugly number. Ugly numbers are positive integers that are divisible by a, b, or c. Example 1: Input: n = 3, a = 2, b = 3, c = 5 Output: 4 Explanation: The ugly numbers are 2, 3, 4, 5, 6, 8, 9, 10... The 3rd is 4. Example 2: Input: n = 4, a = 2, b = 3, c = 4 Output: 6 Explanation: The ugly numbers are 2, 3, 4, 6, 8, 9, 10, 12... The 4th is 6. Example 3: Input: n = 5, a = 2, b = 11, c = 13 Output: 10 Explanation: The ugly numbers are 2, 4, 6, 8, 10, 11, 12, 13... The 5th is 10. Example 4: Input: n = 1000000000, a = 2, b = 217983653, c = 336916467 Output: 1999999984 Constraints: 1 <= n, a, b, c <= 109 1 <= a * b * c <= 1018 It is guaranteed that the result will be in range [1, 2 * 109].