Little Susie listens to fairy tales before bed every day. Today's fairy tale was about wood cutters and the little girl immediately started imagining the choppers cutting wood. She imagined the situation that is described below.

There are n trees located along the road at points with coordinates x1, x2, ..., xn. Each tree has its height hi. Woodcutters can cut down a tree and fell it to the left or to the right. After that it occupies one of the segments [xi - hi, xi] or [xi;xi + hi]. The tree that is not cut down occupies a single point with coordinate xi. Woodcutters can fell a tree if the segment to be occupied by the fallen tree doesn't contain any occupied point. The woodcutters want to process as many trees as possible, so Susie wonders, what is the maximum number of trees to fell. 

Input

The first line contains integer n (1 ≤ n ≤ 105) — the number of trees.

Next n lines contain pairs of integers xi, hi (1 ≤ xi, hi ≤ 109) — the coordinate and the height of the і-th tree.

The pairs are given in the order of ascending xi. No two trees are located at the point with the same coordinate.

Output

Print a single number — the maximum number of trees that you can cut down by the given rules.

Examples

Input

5
1 2
2 1
5 10
10 9
19 1


Output

3


Input

5
1 2
2 1
5 10
10 9
20 1


Output

4

Note

In the first sample you can fell the trees like that: 

  * fell the 1-st tree to the left — now it occupies segment [ - 1;1]
  * fell the 2-nd tree to the right — now it occupies segment [2;3]
  * leave the 3-rd tree — it occupies point 5
  * leave the 4-th tree — it occupies point 10
  * fell the 5-th tree to the right — now it occupies segment [19;20]



In the second sample you can also fell 4-th tree to the right, after that it will occupy segment [10;19].
import java.io.*;
import java.util.*;
import java.math.*; // for bigInteger

public class practice {   

    private final static int M = (int)1e9+7;
	
    private static final InputReader scan = new InputReader(System.in);
    private static final PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
    private static final StringBuilder sb = new StringBuilder();
       
  	final public static void main(String args[]) throws Exception {
        //scanner scan = new scanner(system.in);
        //scan.usedelimiter("");  // for reading character by character

        int n = scan.nextInt();
        int[][] trees = new int[n+1][2];
        for(int i=0;i<n;++i) {
            trees[i][0]=scan.nextInt();
            trees[i][1]=scan.nextInt();
        }
        trees[n][0]=Integer.MAX_VALUE;
        int count = 1; 
        for(int i=1;i<n;++i) {
            int x = trees[i][0];
            int h = trees[i][1];
            int xl = trees[i-1][0];
            int xr = trees[i+1][0];
            if(x-h>xl) {
                ++count;
            } else if(x+h<xr) {
                ++count;
                trees[i][0]=x+h;
            }
        }
        out.println(count);

        scan.close();
        out.close();
    }

	private final static int m =(int)1e9+7;
	private static class Pair<T,V> {
		T first;
		V second;
		Pair(final T first, final V second) {
			this.first = first;
			this.second = second;
		}
		public boolean equals(Object o) {
			Pair given = (Pair)o;
			if(given.first == first && given.second == second)  return true;
			return false;
		}
		public int hashCode() {
			long temp = (long)(first.hashCode())*31;
			temp = (temp+(long)second.hashCode())%m;
			return (int)temp;
		}
	}

    static class InputReader {

        private InputStream stream;
        private byte[] buf = new byte[8192];
        private int curChar;
        private int snumChars;
        private SpaceCharFilter filter;

        public InputReader(final InputStream stream) {
            this.stream = stream;
        }

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

        public int nextInt() {
            int c = snext();
            while (isSpaceChar(c))
                c = snext();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = snext();
            }

            int res = 0;

            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = snext();
            } while (!isSpaceChar(c));

            return res * sgn;
        }

        public long nextLong() {
            int c = snext();
            while (isSpaceChar(c))
                c = snext();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = snext();
            }

            long res = 0;

            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = snext();
            } while (!isSpaceChar(c));

            return res * sgn;
        }

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

        public boolean isSpaceChar(int c) {
            if (filter != null)
                return filter.isSpaceChar(c);
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);
        }
        
        public void close() throws IOException {
            if(stream==null) {
                return;
            }
            stream.close();
        }
    }

    public static void debug(final int[] ...var) {
        for(final int[] row : var) {
            debug(row);
        }
    }

    public static void debug(final long[] ...var) {
        for(final long[] row : var) {
            debug(row);
        }
    }

    public static void debug(final String[] ...var) {
        for(final String[] row : var) {
            debug(row);
        }
    }

    public static void debug(final double[] ...var) {
        for(final double[] row : var) {
            debug(row);
        }
    }

    public static void debug(final char[] ...var) {
        for(final char[] row : var) {
            debug(row);
        }
    }

    public static void debug(final int ...var) {
        for(final int i:var)  System.err.print(i+" ");
        System.err.println();
    }
    public static void debug(final String ...var) {
        for(final String i:var)  System.err.print(i+" ");
        System.err.println();
    }
    public static void debug(final double ...var) {
        for(final double i:var)  System.err.print(i+" ");
        System.err.println();
    }
    
    public static void debug(final long ...var) {
        for(final long i:var)  System.err.print(i+" ");
        System.err.println();
    }
    
    public static void debug(final char ...var) {
        for(final char c:var)  System.err.print(c+" ");
        System.err.println();
    }

    /*
    public static <T> void debug(T ...varargs) {
        // Warning
        // Heap Pollution might occur
        // this overrides even 1d and 2d array methods as it is an object... 
        // + i am not using object based array like Integer[]
        // I am using int[] so that is a problem as i need Wrapper class as an argument
        for(T val:varargs)  System.err.printf("%s ",val);
        System.err.println();
    }
    */
}
