https://codeforces.com/contest/1111/problem/DWe first find the generating function of whole elements.\begin{align} (1+x^\bigcirc)(1+x^\bigcirc) \cdots (1+x^\bigcirc) \end{align}Dividing $(1+x^\bigcirc)^{-1}$, we obtain the answer. #include <stdio.h></stdio.h>…