Russian Doll Envelopes

Statement

You are given a 2D array of integers, envelopes, where each element envelopes[i] = [wi, hi] represents the width and height of an envelope. An envelope can fit inside another if and only if its width and height are strictly smaller than the width and height of the other envelope. The task is to determine the maximum number of envelopes that can be nested inside each other, similar to Russian dollsRussian dolls, also known as stacking dolls or nesting dolls, are a set of wooden dolls of decreasing size placed one inside another. .

Constraints:

• $1\leq$ envelopes.length $\leq 10^3$

• envelopes[i].length $== 2$

• $1\leq$ wi, hi $\leq 10^4$

Examples