n = int(input())
li = [list(map(int,input().split())) for _ in range(n)]

ans = 0
cnt = 0
li.sort()
temp = []

while True:
    arr = []
    check = -10**10
    if len(temp) == 0:
        for i in range(n):
            s = li[i][0] - li[i][1]
            if check > s:
                arr.append(i-1)
                arr.append(i)
            check = li[i][0] + li[i][1]
    else:
        for i in temp:
            s = li[i][0] - li[i][1]
            if check > s:
                arr.append(i-1)
                arr.append(i)
            check = li[i][0] + li[i][1]
    if len(arr) == 0:
        break
    arr = list(set(arr))
    temp = arr
    t = -2
    for index,i in enumerate(arr):
        if t == -2:
            t = i
        elif t+1 == i:
            del temp[index]
            t = -2
            ans += 1
        else:
            t = i

print(n-ans)