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

#	!/bin/env python3
#	coding: UTF-8


#	✪ H4WK3yE乡
#	Mohd. Farhan Tahir
#	Indian Institute Of Information Technology and Management,Gwalior

#	Question Link
#
#

# ///==========Libraries, Constants and Functions=============///


import sys

inf = float("inf")
mod = 1000000007


def get_array(): return list(map(int, sys.stdin.readline().split()))


def get_ints(): return map(int, sys.stdin.readline().split())


def input(): return sys.stdin.readline()

# ///==========MAIN=============///


def solve():
    dp[0][0] = 1  # 1st tree can be cut to left
    # can be cut to right only if it doesnt covers the second tree
    dp[0][1] = 1 if n > 1 and position[0]+height[0] < position[1] else 0
    dp[0][2] = 1
    for i in range(1, n):
        # not cutting
        dp[i][2] = max(dp[i-1][0], dp[i-1][1], dp[i-1][2])

        # cutting to left
        dp[i][0] = dp[i-1][0]

        if position[i]-height[i] > position[i-1]:  # if tree doesnt reaches the previous tree it can be cut to the left
            dp[i][0] = max(dp[i-1][0], dp[i-1][2])+1
            # if cutting tree to left and cutting previous tree to right doesnt
            # touch we can cut previous tree to right
        if position[i]-height[i] > position[i-1]+height[i-1]:
            dp[i][0] = max(dp[i-1][0], dp[i-1][1]+1)

        # cutting to right
        if i < n-1 and position[i]+height[i] >= position[i+1]:
            continue
        dp[i][1] = max(dp[i-1][0], dp[i-1][1], dp[i-1][2])+1


if __name__ == "__main__":
    n = int(input())
    position = [0]*n
    height = [0]*n
    for i in range(n):
        position[i], height[i] = get_ints()
    dp = [[0]*3 for _ in range(n)]
    # dp[i][0] if ith tree is tried to cut left
    # dp[i][1] if ith three is tried to cut right
    # dp[i][2] if ith tree is not cut
    solve()
    print(max(dp[-1][0], dp[-1][1], dp[-1][2]))
