#!/bin/python3

import math

import os

import random

import re

import sys

def max_luck_balance(contests, num_can_lose):

"""

Returns a single integer denoting the maximum amount of luck Lena can have

after all the contests.

"""

balance = 0

# We can lose all unimportant contests.

unimportant_contests = [contest for contest in contests if contest[1] == 0]

for contest_luck, _is_important in unimportant_contests:

balance += contest_luck

# Sort the important contests in descending order of luck balance.

important_contests = sorted(

[contest for contest in contests if contest[1] == 1], reverse=True)

# We want to lose as many of the high balance contests as possible.

contests_to_lose = (important_contests)[:num_can_lose]

# We must win the remaining contests.

contests_to_win = (important_contests)[num_can_lose:]

for contest_luck, _is_important in contests_to_lose:

balance += contest_luck

for contest_luck, _is_important in contests_to_win:

balance -= contest_luck

return balance

if __name__ == '__main__':

num_contests, num_can_lose = map(int, input().split())

contests = []

for _ in range(num_contests):

contests.append(tuple(map(int, input().rstrip().split())))

result = max_luck_balance(contests, num_can_lose)

print(result)