Problem B - Choose and divide
The binomial coefficient C(m,n) is defined as
m!
C(m,n) = --------
n!(m-n)!
Given four natural numbers p, q, r, and s,
compute the the result of dividing C(p,q) by C(r,s).
The Input
Input consists of a sequence of lines. Each line contains four non-negative
integer numbers giving values for p, q, r, and
s, respectively, separated by a single space. All the numbers
will be smaller than 10,000 with p>=q and r>=s.
The Output
For each line of input, print a single line containing a real number
with 5 digits of precision in the fraction, giving the number as
described above. You may assume the result is not greater than
100,000,000.
Sample Input
10 5 14 9
93 45 84 59
145 95 143 92
995 487 996 488
2000 1000 1999 999
9998 4999 9996 4998
Output for Sample Input
0.12587
505606.46055
1.28223
0.48996
2.00000
3.99960