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


def main():
    T = int(raw_input())
    if T == 1:
        print "1"
        return
    trees = []
    while T:
        arr = raw_input()
        arr = arr.split(' ')
        arr = map(int, arr)
        arr.append(0)
        trees.append(arr)
        T -= 1
    
    trees[0][2] = 2
    trees[-1][2] = 2
    cut = 0
    for i in range(len(trees)):
        tree = trees[i]
        if tree[2] == 0:
            b_tree = trees[i-1]
            a_tree = trees[i+1]
            
            x_b_t = determine_dis(b_tree)
            x_a_t = determine_dis(a_tree)
            
            x_t_l = tree[0] - tree[1]
            x_t_r = tree[0] + tree[1]

            if x_t_l > x_b_t:
                tree[2] = 1
                cut += 1
            elif x_t_r < x_a_t:
                tree[2] = 3
                cut += 1
    print cut + 2

def determine_dis(tree):
    if tree[2] == 1 or tree[2] == 0 or tree[2] == 2:
        return tree[0]
    else:
        return tree[0] + tree[1]


if __name__ == '__main__':
    main()
