spoj#NDIV. n-divisors
n-divisors
We all know about prime numbers, prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.
We can Classify the numbers by its number of divisors, as n-divisors-numbers, for example number 1 is 1-divisor number, number 4 is 3-divisors-number... etc.
Note: All prime numbers are 2-divisors numbers.
Example:
8 is a 4-divisors-number [1, 2, 4, 8].
Input
Three integers a, b, n.
Output
Print single line the number of n-divisors numbers between a and b inclusive.
Example
Input: 1 7 2</p>Output: 4
Constraints
1 <= a, b <=10^9
0 <= b - a <= 10^4
1 <= n <= 100