P2652 Straight Flush

A straight flush refers to some playing cards whose suits are the same and whose ranks are consecutive.

Now I have $n$ playing cards, but they may not form a straight flush. I want to know the minimum number of cards I need to replace so that all $n$ cards form a straight flush.

The first line contains an integer $n$, indicating the number of playing cards. Then $n$ lines follow, each containing two integers $a_{i}$ and $b_{i}$. Here, $a_{i}$ denotes the suit of the $i$-th card, and $b_{i}$ denotes the rank of the $i$-th card.

Output a single integer on one line, indicating the minimum number of cards that need to be replaced to achieve the goal.

- For $30\%$ of the testdata, $n \le 10$. - For $60\%$ of the testdata, $n \le 10^{5}$, $1 \le a_{i} \le 10^{5}$, $1 \le b_{i} \le n$. - For $100\%$ of the testdata, $n \le 10^{5}$, $1 \le a_{i}, b_{i} \le 10^{9}$. Translated by ChatGPT 5