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

#include <bits/stdc++.h>
using namespace std;
template <typename T>
T gcd(T x, T y) {
  if (y == 0)
    return x;
  else
    return gcd(y, x % y);
}
template <class T>
T euclideanDistance(T x1, T x2, T y1, T y2) {
  return sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
}
template <class T>
T digitSum(T n) {
  T sum = 0;
  while (n > 0) sum += n % 10, n /= 10;
  return sum;
}
const double INF = 1e+9;
const double INFLL = 1e+18;
const double EPS = 1e-9;
const double PI = acos(-1);
const int knightDir[8][2] = {{-2, -1}, {-2, 1}, {-1, 2},  {1, 2},
                             {2, -1},  {2, 1},  {-1, -2}, {1, -2}};
const int dx[] = {0, 1, 0, -1};
const int dy[] = {1, 0, -1, 0};
const long long int MOD = 1000000000 + 7;
int price[2000005] = {0, 1, 5, 8, 9, 10, 17, 17, 20, 24, 30};
int dp[2000005], lt[2000005], pos[2000005], ht[2000005], n;
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d%d", &pos[i], &ht[i]);
  }
  dp[1] = 1;
  lt[1] = pos[1];
  for (int i = 2; i <= n; i++) {
    int temp = i == n ? INT_MAX : pos[i + 1];
    if (pos[i] - lt[i - 1] > ht[i]) {
      dp[i] = dp[i - 1] + 1;
      lt[i] = pos[i];
    } else if (pos[i] + ht[i] < temp) {
      dp[i] = dp[i - 1] + 1;
      lt[i] = pos[i] + ht[i];
    } else {
      dp[i] = dp[i - 1];
      lt[i] = max(pos[i], lt[i]);
    }
  }
  if (n == 2)
    printf("2\n");
  else
    printf("%d\n", dp[n]);
}
