import sys

data = list()
data_i = 0

def nextInt():
    global data, data_i

    if data_i >= len(data):
        data = list(map(int, input().split()))
        data_i = 0

    data_i = data_i + 1
    return data[data_i - 1]


def main():
    similarPairs = 0

    totalRows = nextInt()
    T = nextInt()
    mapObject = {}

    for i in range(0, totalRows - 1):
        data = nextInt()
        cdata = nextInt()
        currValue = cdata

        mapObject[cdata] = data

        if cdata in mapObject:
            parent = mapObject[cdata]
            if abs(parent - currValue) <= T:
                similarPairs = similarPairs + 1
            cdata = parent

    print(similarPairs)

main()