4
10 4
15 1
19 3
20 1
 2
1 999999999
1000000000 1000000000
 67
1 1
3 8
4 10
7 8
9 2
10 1
11 5
12 8
13 4
16 6
18 3
19 3
22 5
24 6
27 5
28 3
29 3
30 5
32 5
33 10
34 7
35 8
36 5
41 3
42 2
43 5
46 4
48 4
49 9
52 4
53 9
55 1
56 4
59 7
68 7
69 4
71 9
72 10
74 5
76 4
77 9
80 7
81 9
82 5
83 5
84 9
85 7
86 9
87 4
88 7
89 10
90 3
91 5
92 10
93 5
94 8
95 4
96 2
97 10
98 1
99 3
100 1
101 5
102 4
103 8
104 8
105 8
 10
999999900 1000000000
999999901 1000000000
999999902 1000000000
999999903 1000000000
999999904 1000000000
999999905 1000000000
999999906 1000000000
999999907 1000000000
999999908 1000000000
999999909 1000000000
 35
1 7
3 11
6 12
7 6
8 5
9 11
15 3
16 10
22 2
23 3
25 7
27 3
34 5
35 10
37 3
39 4
40 5
41 1
44 1
47 7
48 11
50 6
52 5
57 2
58 7
60 4
62 1
67 3
68 12
69 8
70 1
71 5
72 5
73 6
74 4
 1
1000000000 1000000000
 2
100000000 1000000000
1000000000 1000000000
 10
7 12
10 2
12 2
15 1
19 2
20 1
53 25
63 10
75 12
87 1
 3
1 1
1000 1000
1000000000 1000000000
 40
1 1
2 1
3 1
4 1
5 1
6 1
7 1
8 1
9 1
10 1
11 1
12 1
13 1
14 1
15 1
16 1
17 1
18 1
19 1
20 1
21 1
22 1
23 1
24 1
25 1
26 1
27 1
28 1
29 1
30 1
31 1
32 1
33 1
34 1
35 1
36 1
37 1
38 1
39 1
40 1

4
 2
 5
 2
 10
 1
 2
 9
 3
 2

n = int(raw_input())
a = [map(int, raw_input().split()) for _ in xrange(n)]
CUT_LEFT, CUT_RIGHT, NOT_CUT = 0, 1, 2
dp = [[0 for _ in xrange(n)] for _ in xrange(3)]
dp[CUT_LEFT][0] = 1
if n - 1 == 0 or sum(a[0]) < a[1][0]:
    dp[CUT_RIGHT][0] = 1
for i in xrange(1, n):
    prevX, prevH = a[i - 1]
    curX, curH = a[i]

    dp[NOT_CUT][i] = max(dp[NOT_CUT][i - 1], dp[CUT_LEFT][i - 1])
    if prevX + prevH < curX and dp[CUT_RIGHT][i - 1] > dp[NOT_CUT][i]:
        dp[NOT_CUT][i] = dp[CUT_RIGHT][i - 1]

    if prevX < curX - curH:
        dp[CUT_LEFT][i] = max(dp[CUT_LEFT][i - 1], dp[NOT_CUT][i - 1]) + 1
    if prevX + prevH < curX - curH and dp[CUT_RIGHT][i - 1] + 1 > dp[CUT_LEFT][i]:
        dp[CUT_LEFT][i] = dp[CUT_RIGHT][i - 1] + 1
    if dp[CUT_LEFT][i] == 0:
        max(dp[CUT_LEFT][i - 1], dp[NOT_CUT][i - 1], dp[CUT_RIGHT][i - 1])

    dp[CUT_RIGHT][i] = max(dp[CUT_LEFT][i - 1], dp[NOT_CUT][i - 1], dp[CUT_RIGHT][i - 1]) \
                       + (i == n - 1 or curX + curH < a[i + 1][0])

print max(dp[CUT_LEFT][n - 1], dp[NOT_CUT][n - 1], dp[CUT_RIGHT][n - 1])