### ** sale**

## Problem Description

There are *N* items in the supermarket, each of them with a normal price *A*_{i} and sale price *B*_{i}.

Rar the Cat wants to buy *X* items during the non-sale period, and *Y* items during a sale period, without buying two of the same items.

Help Rar minimise the total cost of the items he buys.

## Input

The first line of input will contain three integers, *N*, *X* and *Y*.

The next *N* lines of input will contain two integers each, representing *A*_{i} and *B*_{i}.

## Output

The output should contain one integer, the minimum total cost.

## Limits

0 ≤ X, Y ≤ N, X + Y ≤ N, 0 ≤ *A*_{i}, *B*_{i} ≤ 10^{9}.

Subtask 1 (4%): 1 ≤ N ≤ 12.

Subtask 2 (10%): 1 ≤ N ≤ 50.

Subtask 3 (14%): 1 ≤ N ≤ 300.

Subtask 4 (14%): 1 ≤ N ≤ 2 000.

Subtask 5 (7%): 1 ≤ N ≤ 100 000, B_{i} = 0.

Subtask 6 (13%): 1 ≤ N ≤ 100 000, Y = 1.

Subtask 7 (12%): 1 ≤ N ≤ 100 000, X + Y = N.

Subtask 8 (11%): 1 ≤ N ≤ 100 000.

Subtask 9 (15%): 1 ≤ N ≤ 500 000.

Subtask 10 (0%): Sample Testcases

## Sample Testcase 1

### Input

3 1 1
1 3
4 1
5 6

### Output

2

## Sample Testcase 2

### Input

4 2 1
3 4
0 3
4 5
3 10

### Output

7