Another Contest 5 Problem 3 - Cutting Cheese Costs

Points: 5 (partial)

Time limit: 1.0s

Memory limit: 256M

Problem type

Tudor is buying $N$ ~N~ blocks of cheese. Each block of cheese has a regular price and a discounted price.

Tudor has $K$ ~K~ coupons that allow him to buy a block of cheese for the discounted price instead of the regular price. Each coupon can be used for exactly one block of cheese.

Given that Tudor wants to buy all $N$ ~N~ blocks of cheese, compute the minimum amount of money he must spend.

Constraints

$1 \le N \le 10^5$ ~1 \le N \le 10^5~

$0 \le K \le N$ ~0 \le K \le N~

$1 \le d_i \le p_i \le 10^9$ ~1 \le d_i \le p_i \le 10^9~

Input Specification

The first line contains two space separated integers, $N$ ~N~ and $K$ ~K~.

The next $N$ ~N~ lines each contain two space separated integers, $p_i$ ~p_i~ and $d_i$ ~d_i~ representing the regular price and discounted price of block $i$ ~i~, respectively.

Output Specification

Output the minimum amount of money Tudor must spend.

Sample Input

2 1
100 0
10 10

Sample Output

Comments

3

tappbros commented on July 24, 2020, 8:59 p.m. ← edited →

This has nothing to do with cutting cheese. What. I mean, I know it's a block of cheese which you can cut, but, like...

16

Kirito commented on July 24, 2020, 11:00 p.m.

It is not the cheese that is being cut, but the price of said cheese.

3

notpeachay420 commented on Oct. 30, 2020, 5:11 p.m.

ohhhh that makes more sense

1

Pleedoh commented on Oct. 21, 2019, 2:19 a.m. ← edited →

Can anyone help me with WA (Presentation Error, check your whitespace)?

I literally just output the answer, there is no whitespace...

6

Tzak commented on Oct. 21, 2019, 4:27 a.m.

You should place a \n character at the end of your output.