ENG  RUSTimus Online Judge
Online Judge
Problems
Authors
Online contests
About Online Judge
Frequently asked questions
Site news
Webboard
Links
Problem set
Submit solution
Judge status
Guide
Register
Update your info
Authors ranklist
Current contest
Scheduled contests
Past contests
Rules

1057. Amount of Degrees

Time limit: 1.0 second
Memory limit: 64 MB
Create a code to determine the amount of integers, lying in the set [X; Y] and being a sum of exactly K different integer degrees of the integer B.
Example. Let X = 15, Y = 20, K = 2, B = 2. By this example three integers are the sum of exactly two integer degrees of number 2:
17 = 24 + 20,
18 = 24 + 21,
20 = 24 + 22.

Input

The first line contains integers X and Y (1 ≤ X ≤ Y ≤ 231 − 1). The next two lines contain integers K and B (1 ≤ K ≤ 20; 2 ≤ B ≤ 10).

Output

Output the amount of integers, lying between X and Y, being a sum of exactly K different integer degrees of B.

Sample

inputoutput
15 20
2
2
3
Problem Source: Rybinsk State Avia Academy