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.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.BufferedWriter;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.io.IOException;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) throws IOException {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        OutputWriter out = new OutputWriter(outputStream);
        CWoodcutters solver = new CWoodcutters();
        solver.solve(1, in, out);
        out.close();
    }

    static class CWoodcutters {
        public void solve(int testNumber, InputReader in, OutputWriter out) throws IOException {
            int n = in.nextInt();
            byte isFlipped[] = new byte[n];
            for (int i = 0; i < n; i++)
                isFlipped[i] = 0;
            isFlipped[0] = -1;//Flipped left
            int xh[][] = in.nextIntMatrix(n, 2);
            int countFlipped = 1;
            //out.printLine(xh[0][0]);
            for (int i = 1; i < n; i++) {
                if ((isFlipped[i - 1] == 1 && (xh[i][1] + xh[i - 1][1] < xh[i][0] - xh[i - 1][0])) || ((!(isFlipped[i - 1] == 1)) && (xh[i][1] < xh[i][0] - xh[i - 1][0]))) {
                    isFlipped[i] = -1;
                    countFlipped++;
                    //out.printLine(xh[i][0]+"\t"+xh[i][1]);
                } else if (i == n - 1 || xh[i][1] < xh[i + 1][0] - xh[i][0]) {
                    isFlipped[i] = 1;
                    countFlipped++;
                    //out.printLine(xh[i][0]);
                }
            }
            out.printLine(countFlipped);
        }

    }

    static class InputReader {
        private static final int DEFAULT_BUFFER_SIZE = 1 << 16;
        private static final InputStream DEFAULT_STREAM = System.in;
        private int c;
        private byte[] buf;
        private int bufferSize;
        private int bufIndex;
        private int numBytesRead;
        private InputStream stream;
        private static final byte EOF = -1;
        private static final byte SPACE = 32;
        private static final byte DASH = 45;
        private char[] charBuffer;
        private static byte[] bytes = new byte[58];
        private static int[] ints = new int[58];
        private static char[] chars = new char[128];

        static {
            char ch = ' ';
            int value = 0;
            byte _byte = 0;
            for (int i = 48; i < 58; i++) bytes[i] = _byte++;
            for (int i = 48; i < 58; i++) ints[i] = value++;
            for (int i = 32; i < 128; i++) chars[i] = ch++;
        }

        public InputReader() {
            this(DEFAULT_STREAM, DEFAULT_BUFFER_SIZE);
        }

        public InputReader(int bufferSize) {
            this(DEFAULT_STREAM, bufferSize);
        }

        public InputReader(InputStream stream) {
            this(stream, DEFAULT_BUFFER_SIZE);
        }

        public InputReader(InputStream stream, int bufferSize) {
            if (stream == null || bufferSize <= 0)
                throw new IllegalArgumentException();
            buf = new byte[bufferSize];
            charBuffer = new char[128];
            this.bufferSize = bufferSize;
            this.stream = stream;
        }

        private int readJunk(int token) throws IOException {

            if (numBytesRead == EOF) return EOF;

            // Seek to the first valid position index
            do {

                while (bufIndex < numBytesRead) {
                    if (buf[bufIndex] > token) return 0;
                    bufIndex++;
                }

                // reload buffer
                numBytesRead = stream.read(buf);
                if (numBytesRead == EOF) return EOF;
                bufIndex = 0;

            } while (true);

        }

        public int nextInt() throws IOException {

            if (readJunk(DASH - 1) == EOF) throw new IOException();
            int sgn = 1, res = 0;

            c = buf[bufIndex];
            if (c == DASH) {
                sgn = -1;
                bufIndex++;
            }

            do {

                while (bufIndex < numBytesRead) {
                    if (buf[bufIndex] > SPACE) {
                        res = (res << 3) + (res << 1);
                        res += ints[buf[bufIndex++]];
                    } else {
                        bufIndex++;
                        return res * sgn;
                    }
                }

                // Reload buffer
                numBytesRead = stream.read(buf);
                if (numBytesRead == EOF) return res * sgn;
                bufIndex = 0;

            } while (true);

        }

        public int[][] nextIntMatrix(int rows, int cols) throws IOException {
            int[][] matrix = new int[rows][cols];
            for (int i = 0; i < rows; i++)
                for (int j = 0; j < cols; j++)
                    matrix[i][j] = nextInt();
            return matrix;
        }

    }

    static class OutputWriter {
        private final PrintWriter writer;

        public OutputWriter(OutputStream outputStream) {
            writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
        }

        public OutputWriter(Writer writer) {
            this.writer = new PrintWriter(writer);
        }

        public void print(Object... objects) {
            for (int i = 0; i < objects.length; i++) {
                if (i != 0)
                    writer.print(' ');
                writer.print(objects[i]);
            }
        }

        public void printLine(Object... objects) {
            print(objects);
            writer.println();
        }

        public void close() {
            writer.close();
        }

    }
}

