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

import java.io.IOException;
import java.util.ArrayList;
import java.util.InputMismatchException;

public class Q1 {
    public static void main(String[] args) {
        FasterScanner s = new FasterScanner();
        
       int n=s.nextInt();
       long p[] =new long[n];
       long h[] =new long[n];
       
       for(int i=0;i<n;i++)
       {
           p[i]=s.nextLong();
           h[i]=s.nextLong();
       }
//
       
       
       long p2[]=new long[n];
       long[] c1=new long[n];
       long[] c2=new long[n];
       
       c1[0]=1;
       c2[0]=1;
       p2[0]=p[0]+h[0];
       
       for(int i=1;i<n;i++)
       {
//         System.out.println(i);
//         System.out.println(p[i]+" "+h[i]);
//         System.out.println(c1[i-1]+" "+c2[i-1]+" "+p2[i-1]);
           if(p[i]-h[i]>p2[i-1])
           {
               c1[i]=c2[i-1]+1;
           }
           else if(p[i]-h[i]>p[i-1])
           {
               c1[i]=c1[i-1]+1;
           }
           else if(p[i]>p2[i-1])
               c1[i]=c2[i-1];
           else
               c1[i]=c1[i-1];
           p2[i]=p[i]+h[i];
           if(p[i]>p2[i-1])
               c2[i]=c2[i-1]+1;
           else
               c2[i]=c1[i-1]+1;
       }
       System.out.println(c2[n-1]);
       
       
       
       
       
       
       
       
       
       
       
//       long pointFilled=p[0];
//       for(int i=1;i<n-1;i++)
//       {
//         if(p[i]-h[i]>pointFilled)
//         {
//             count++;
//             pointFilled=p[i];
//         }
//         else if(p[i]+h[i]<p[i+1])
//         {
//             count++;
//             pointFilled=p[i]+h[i];
//         }
//       }
//       if(n!=1)
//         count++;
//       System.out.println(count);
//       
    }

   
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    public static class FasterScanner {
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;

        public int read() {
            if (numChars == -1)
                throw new InputMismatchException();
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = System.in.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0)
                    return -1;
            }
            return buf[curChar++];
        }

        public String nextLine() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isEndOfLine(c));
            return res.toString();
        }

        public String nextString() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public long nextLong() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public int nextInt() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }
           
        public int[] nextIntArray(int n) {
            int[] arr = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = nextInt();
            }
            return arr;
        }
       
        public long[] nextLongArray(int n) {
            long[] arr = new long[n];
            for (int i = 0; i < n; i++) {
                arr[i] = nextLong();
            }
            return arr;
        }

        private boolean isSpaceChar(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        private boolean isEndOfLine(int c) {
            return c == '\n' || c == '\r' || c == -1;
        }
    }
}