Pascal Multiple

The $(i,j)$th binomial coefficient, denoted $C(i,j)$, is the (zero-indexed) $j$th entry of the (zero-indexed) $i$th row in Pascal's triangle:

1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
...

where $C(0,0) = 1$ and the $(i+1)$st row can be computed from the $i$th row using the recursion $C(i+1, j) = C(i,j) + C(i, j-1),$ treating as $0$ any out-of-bounds entries of the triangle on the right-hand side.

Given $N$ and $K$, compute how many entries in the first $N+1$ rows of Pascal's triangle are multiples of $K$. To be precise: for how many pairs of indices $(i,j)$ with $0\leq i\leq N$ and $0 \leq j \leq i$, is $C(i,j)$ divisible by $K$?

The single line of input contains two positive integers $N$ $(1 \leq N \leq 10^3)$ and $K$ $(1 \leq K \leq N)$, with meaning as described above.

Print the number of entries in the first $N+1$ rows of Pascal's triangle that are divisible by $K$.