import numpy as np

import functools

import math

import scipy

import fractions

import itertools



def solve():

    n = int(eval(input()))

    x, l = [0]*n, [0]*n

    for i in range(n):

        x[i], l[i] = list(map(int, input().split()))

    hoge = []

    for i in range(n):

        hoge.append([x[i]+l[i], x[i]-l[i]])

    hoge.sort()

    t = -1000000000000000000000

    ans = 0

    for i in range(n):

        if t <= hoge[i][1]:

            ans += 1

            t = hoge[i][0]

    print(ans)

    return 0



if __name__ == "__main__":

    solve()
def solve():

    n = int(eval(input()))

    x, l = [0]*n, [0]*n

    for i in range(n):

        x[i], l[i] = list(map(int, input().split()))

    hoge = []

    for i in range(n):

        hoge.append([x[i]+l[i], x[i]-l[i]])

    hoge.sort()

    t = -1000000000000000000000

    ans = 0

    for i in range(n):

        if t <= hoge[i][1]:

            ans += 1

            t = hoge[i][0]

    print(ans)

    return 0

 

if __name__ == "__main__":

    solve()
import numpy as np
import functools
import math
import scipy
import fractions
import itertools


def solve():
    n = int(eval(input()))
    x, l = [0] * n, [0] * n
    for i in range(n):
        x[i], l[i] = list(map(int, input().split()))
    hoge = []
    for i in range(n):
        hoge.append([x[i] + l[i], x[i] - l[i]])
    hoge.sort()
    t = -1000000000000000000000
    ans = 0
    for i in range(n):
        if t <= hoge[i][1]:
            ans += 1
            t = hoge[i][0]
    print(ans)
    return 0


if __name__ == "__main__":
    solve()

def solve():
    n = int(eval(input()))
    x, l = [0] * n, [0] * n
    for i in range(n):
        x[i], l[i] = list(map(int, input().split()))
    hoge = []
    for i in range(n):
        hoge.append([x[i] + l[i], x[i] - l[i]])
    hoge.sort()
    t = -1000000000000000000000
    ans = 0
    for i in range(n):
        if t <= hoge[i][1]:
            ans += 1
            t = hoge[i][0]
    print(ans)
    return 0


if __name__ == "__main__":
    solve()

-import numpy as np -import functools -import math -import scipy -import fractions -import itertools - -