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

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

    static class DIslandsWar {
        public void solve(int testNumber, InputReader in, OutputWriter out) {
            int n = in.nextInt();
            int nRequests = in.nextInt();
            Segment[] a = new Segment[nRequests];
            for (int i = 0; i < nRequests; i++) {
                a[i] = new Segment(in.nextInt(), in.nextInt() - 1);
            }

            Arrays.sort(a);
            int ret = 1;
            Segment common = new Segment(1, n - 1);
            for (int i = 0; i < nRequests; i++) {
                Segment seg = a[i];
                if (!seg.intersects(common)) {
                    ret++;
                    common.left = seg.left;
                    common.right = seg.right;
                } else {
                    common.left = seg.left;
                    common.right = Math.min(common.right, seg.right);
                }
            }

            out.println(ret);

        }

        private class Segment implements Comparable<Segment> {
            private int left;
            private int right;

            private Segment(int left, int right) {
                this.left = left;
                this.right = right;
            }

            private boolean intersects(Segment other) {
                return left <= other.right;
            }

            public int compareTo(Segment other) {
                if (left == other.left) {
                    return Integer.compare(right, other.right);
                }
                return Integer.compare(left, other.left);
            }

            public String toString() {
                return "(" + left + " " + right + ")";
            }

        }

    }

    static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private InputReader.SpaceCharFilter filter;

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

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

        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 boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

        public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        }

    }

    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 close() {
            writer.close();
        }

        public void println(int i) {
            writer.println(i);
        }

    }
}



Measured memory_bytes: 27400