Problems
Combination
Combination
How many numbers are divisible by the prime number p in the first n rows of Pascal Triangle? In other words, find the number of pairs (j, i) (0 ≤ j ≤ i < n) so that C(i, j) is divisible by p. Here
Input
The first line contains two integer numbers n, p (1 ≤ n ≤ 107
, 3 ≤ p ≤ 100).
Output
Print the answer.
Input example #1
5 3
Output example #1
3
Input example #2
100 7
Output example #2
2689