P7628 [COCI 2011/2012 #1] PLES

There are $N$ boys and $N$ girls at a dance party, and we know their heights. Each person can dance with at most one partner. Each boy either wants to dance with a girl taller than him, or with a girl shorter than him. Similarly, each girl either wants to dance with a boy taller than her, or with a boy shorter than her. No boy and girl of the same height want to dance with each other. If everyone’s wishes are respected, find the maximum number of dancing pairs.

The first line contains a positive integer $N$. The next $N$ lines each contain an integer $A_i$. The absolute value of $A_i$ is the height of the $i$-th boy. If $A_i$ is positive, it means the $i$-th boy wants to dance with a girl taller than him; if $A_i$ is negative, it means the $i$-th boy wants to dance with a girl shorter than him. The next $N$ lines each contain an integer $B_j$. The absolute value of $B_j$ is the height of the $j$-th girl. If $B_j$ is positive, it means the $j$-th girl wants to dance with a boy taller than her; if $B_j$ is negative, it means the $j$-th girl wants to dance with a boy shorter than her.

Output one line with one integer, the maximum number of dancing pairs.

#### Constraints For $100\%$ of the testdata, $1 \le N \le 10^5$, $1500 \le |A_i,B_j| \le 2500$. #### Notes The score setting of this problem follows the original COCI problem, with a full score of $110$. Translated from **[COCI2011-2012](https://hsin.hr/coci/archive/2011_2012/) [CONTEST #1](https://hsin.hr/coci/archive/2011_2012/contest1_tasks.pdf)** ___T4 PLES___. Translated by ChatGPT 5