An Interesting Sequence

You are given an integer $K$. Consider an integer sequence $A = [A_1, A_2, \ldots, A_N]$. Define another sequence $S$ of length $N$, such that $S_i = A_1 + A_2 + \ldots + A_i$ for each $1 \leq i \leq N$. $A$ is said to be *interesting* if $A_i + S_i = K$ for every $1 \leq i \leq N$. Find the **maximum** length of an interesting sequence. If there are no interesting sequences, print $0$. ### I