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;
long long int power(long long int x, long long int n) {
  if (n == 0)
    return 1;
  else if (n == 1)
    return x;
  else if (n % 2 == 0)
    return (power(x, n / 2) % 1000000007 * power(x, n / 2) % 1000000007) %
           1000000007;
  else
    return (x % 1000000007 *
            ((power(x, (n - 1) / 2) % 1000000007 * power(x, (n - 1) / 2) %
              1000000007) %
             1000000007) %
            1000000007) %
           1000000007;
}
long long int isprime(long long int n) {
  long long int i;
  for (i = 2; i <= (long long int)sqrt(n); i++) {
    if (n % i == 0) return 0;
  }
  return 1;
}
void multiply(long long int x[3][3], long long int arr[3][3]) {
  long long int i, j, k;
  long long int y[3][3] = {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}};
  for (k = 0; k < 3; k++) {
    for (i = 0; i < 3; i++) {
      for (j = 0; j < 3; j++)
        y[k][i] =
            (y[k][i] % 1000000007 +
             ((x[k][j] % 1000000007 * arr[j][i] % 1000000007) % 1000000007) %
                 1000000007) %
            1000000007;
    }
  }
  for (i = 0; i < 3; i++) {
    for (j = 0; j < 3; j++) {
      x[i][j] = y[i][j];
    }
  }
}
void power(long long int arr[3][3], long long int n) {
  long long int i, j;
  if (n == 1)
    return;
  else if (n % 2 == 0) {
    power(arr, n / 2);
    multiply(arr, arr);
  } else {
    long long int x[3][3] = {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}};
    for (i = 0; i < 3; i++) {
      for (j = 0; j < 3; j++) x[i][j] = arr[i][j];
    }
    power(arr, n / 2);
    multiply(arr, arr);
    multiply(arr, x);
  }
}
long long int matrixexpo(long long int a, long long int b, long long int c,
                         long long int n) {
  long long int i, j;
  long long int arr[3][3] = {{a, b, c}, {1, 0, 0}, {0, 1, 0}};
  power(arr, n - 2);
  return (((((arr[0][0] % 1000000007 * 4 % 1000000007) % 1000000007) %
                1000000007 +
            ((arr[0][1] % 1000000007 * 2 % 1000000007) % 1000000007) %
                1000000007) %
           1000000007) %
              1000000007 +
          ((arr[0][2] % 1000000007 * 1 % 1000000007) % 1000000007) %
              1000000007) %
         1000000007;
}
int main() {
  long long int n, i, j, c = 2;
  cin >> n;
  long long int arr[n][2];
  for (i = 0; i < n; i++) cin >> arr[i][0] >> arr[i][1];
  if (n == 1)
    cout << 1 << '\n';
  else {
    for (i = 1; i < n - 1; i++) {
      if (arr[i][0] - arr[i][1] > arr[i - 1][0])
        c++;
      else if (arr[i][1] + arr[i][0] < arr[i + 1][0]) {
        c++;
        arr[i][0] = arr[i][1] + arr[i][0];
      }
    }
    cout << c << '\n';
  }
  return 0;
}
