import os, io
input = io.BytesIO(os.read(0, os.fstat(0).st_size)).readline
N, M = map(int, input().split())
com = [tuple(map(int, input().split())) for i in range(N)]
com.sort(key = lambda x:x[1])
cc = []
order = [0] * N
for i in range(N):
cc.append((com[i][0], i))
cc.sort()
for i in range(N):
order[cc[i][1]] = i
S = [0] * 3737858
C = [0] * 3737858
L = [0] * 3737858
R = [0] * 3737858
idx = 0
root = [0] * N
def add():
global idx
idx += 1
return idx
def update(p, x, i, v):
s = 0
e = N - 1
while 1:
S[x] = S[p] + v
C[x] = C[p] + 1
if s == e:break
m = s + e >> 1
if i <= m:
R[x] = R[p]
L[x] = add()
e = m
x = L[x]
p = L[p]
else:
L[x] = L[p]
R[x] = add()
s = m + 1
x = R[x]
p = R[p]
def get(l, r):
k = M
ret = 0
s = 0
e = N - 1
while s < e:
cnt = C[R[r]] - C[R[l]]
m = s + e >> 1
if cnt <= k:
k -= cnt
ret += S[R[r]] - S[R[l]]
l = L[l]
r = L[r]
e = m
else:
r = R[r]
l = R[l]
s = m + 1
return ret + k * (S[r] - S[l])
def dnq(s = 0, e = N - M, opts = 0, opte = N - M):
if s > e:return float('-inf')
m = s + e >> 1
ans = float('-inf')
j = 0
for i in range(max(m, opts), opte + 1):
k = get(root[m], root[i + M]) - 2 * (com[i + M - 1][1] - com[m][1])
if k > ans:
ans = k
j = i
return max(ans, dnq(s, m - 1, opts, j), dnq(m + 1, e, j, opte))
root = [add() for i in range(N + 1)]
for i in range(N):
update(root[i], root[i + 1], order[i], com[i][0])
print(dnq())
