Problem Description Here on earth, our 24-hour day is composed of two parts, each of 12 hours. Each hour in each part has a corresponding hour in the other part separated by 12 hours: the hour essentially measures the duration since the start of the day part. For example, 1 hour in the first part of the day is equivalent to 13, which is 1 hour into the second part of the day. Now, consider the equivalent hours that are both prime numbers. We have 3 such instances for a 24-hour 2-part day: 5~17 7~19 11~23 Accept two natural numbers D, P >1 corresponding respectively to number of hours per day and number of parts in a day separated by a space. D should be divisible by P, meaning that the number of hours per part (D/P) should be a natural number. Calculate the number of instances of equivalent prime hours. Output zero if there is no such instance. Note that we require each equivalent hour in each part in a day to be a prime number. Example: Input: 24 2 Output: 3 (We have 3 instances of equivalent prime hours: 5~17, 7~19 and 11~23.) Constraints 10 <= D < 500 2 <= P < 50 Input Single line consists of two space separated integers, D and P corresponding to number of hours per day and number of parts in a day respectively Output Output must be a single number, corresponding to the number of instances of equivalent prime number, as described above Time Limit 1 Examples Example 1 Input 36 3 Output 2 Explanation In the given test case D = 36 and P = 3 Duration of each day part = 12 2~14~X 3~15~X 5~17~29 - instance of equivalent prime hours 7~19~31 - instance of equivalent prime hours 11~23~X Hence the answers is 2. Example 2 Input 49 7 Output 0 Explanation Duration of each day part = 7 2~9~X~23~X~37~X 3~X~17~X~31~X~X 5~X~19~X~X~X~47 7~X~X~X~X~X~X Hence there are no equivalent prime hours.