import sys
from random import *
from itertools import permutations
from math import gcd
input = lambda: sys.stdin.readline().strip()


def mas():
    return list(map(int, input().split()))
f = open("27_B_5142 (1).txt")
n, m = map(int, f.readline().split())
a = []
for i in range(n):
    x, y = map(int, f.readline().split())
    z = (y + 49) // 50
    a.append([x, y, z])
a.sort()
pref_y = [0] * (n + 1)
pref_z = [0] * (n + 1)
for i in range(1, n + 1):
    pref_y[i] = pref_y[i - 1] + a[i - 1][1]
    pref_z[i] = pref_z[i - 1] + a[i - 1][2]


ans = -1
z = -1
for i in range(n):
    l = -1
    r = i
    while r - l > 1:
        mid = (l + r) >> 1
        if a[i][0] - a[mid][0] <= m:
            r = mid
        else:
            l = mid
    ind1 = r
    l = i
    r = n
    while r - l > 1:
        mid = (l + r) >> 1
        if a[mid][0] - a[i][0] <= m:
            l = mid
        else:
            r = mid
    ind2 = l
    if pref_y[ind2 + 1] - pref_y[ind1] > ans:
        ans = pref_y[ind2 + 1] - pref_y[ind1]
        z = pref_z[ind2 + 1] - pref_z[ind1]
    elif pref_y[ind2 + 1] - pref_y[ind1] == ans and pref_z[ind2 + 1] - pref_z[ind1] < z:
        z = pref_z[ind2 + 1] - pref_z[ind1]

print(z)