question link- https://codeforces.com/contest/1419/problem/B

can anyone please help me to understand this problem?

i am unable to get what exactly we need to find and what is n disjoint squares.

You can think of it as same colored squares should not touch each other.

or maybe you can think as-

Can you divide the n- staircase into n squares such that the squares should fully cover the staircase + all squares should not have any cell in common + there should be no two same colored squares such that they share any edge or corner.

In the above photo n = 6 and the number of the disjoint square are 7 (4 green + 2 yellow + 1 red)

In this photo n = 7 and number of disjoint square = 7

In the question, you have to count the total nice staircase(no. of stairs (n) == disjoint square used) which can be formed using “X” 1 * 1 cell of square.