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ZOJ Problem Set - 2166
Unit Fraction Partition

Time Limit: 2 Seconds      Memory Limit: 65536 KB

A fraction whose numerator is 1 and whose denominator is a positive integer is called a unit fraction. A representation of a positive rational number p/q as the sum of finitely many unit fractions is called a partition of p/q into unit fractions. For example, 1/2 + 1/6 is a partition of 2/3 into unit fractions. The difference in the order of addition is disregarded. For example, we do not distinguish 1/6 + 1/2 from 1/2 + 1/6.

For given four positive integers p, q, a, and n, count the number of partitions of p/q into unit fractions satisfying the following two conditions.

  • The partition is the sum of at most n many unit fractions.
  • The product of the denominators of the unit fractions in the partition is less than or equal to a.

For example, if (p,q,a,n) = (2,3,120,3), you should report 4 since

2/3 = 1/3 + 1/3 = 1/2 + 1/6 = 1/4 + 1/4 + 1/6 = 1/3 + 1/6 + 1/6

enumerates all of the valid partitions.


Input

The input is a sequence of at most 200 data sets followed by a terminator.

A data set is a line containing four positive integers p, q, a, and n satisfying p,q <= 800, a <= 12000 and n <= 7. The integers are separated by a space.

The terminator is composed of just one line which contains four zeros separated by a space. It is not a part of the input data but a mark for the end of the input.


Output

The output should be composed of lines each of which contains a single integer. No other characters should appear in the output.

The output integer corresponding to a data set p, q, a, n should be the number of all partitions of p/q into at most n many unit fractions such that the product of the denominators of the unit fractions is less than or equal to a.


Sample Input

2 3 120 3
2 3 300 3
2 3 299 3
2 3 12 3
2 3 12000 7
54 795 12000 7
2 3 300 1
2 1 200 5
2 4 54 2
0 0 0 0


Sample Output

4
7
6
2
42
1
0
9
3


Source: Asia 2004, Ehime (Japan), Japan Domestic
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