import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Comparator;
import java.util.InputMismatchException;

public class Main {

	InputStream is;
	PrintWriter out;
	String INPUT = "";

	private static final long M = 1000000007;

	void solve() {
		int h = ni();
		int w = ni();
		int n = ni();

		long fact[] = new long[h + w + 1];
		fact[0] = 1;
		for (int i = 1; i <= h + w; i++)
			fact[i] = (fact[i - 1] * i) % M;
		long inv[] = new long[h + w + 1];
		for (int i = 0; i <= h + w; i++)
			inv[i] = power(fact[i], M - 2);

		int[][] a = new int[n + 1][];
		for (int i = 0; i < n; i++)
			a[i] = new int[] { ni() - 1, ni() - 1 };
		a[n] = new int[] { h-1, w-1 };

		Arrays.sort(a, new Comparator<int[]>() {
			public int compare(int[] o1, int[] o2) {
				if (o1[0] == o2[0])
					return o1[1] - o2[1];
				return o1[0] - o2[0];
			}
		});

		long ways[] = new long[n + 1];
		// ways from (0,0,) to a[i]
		for (int i = 0; i <= n; i++) {
			int x = a[i][0];
			int y = a[i][1];
			ways[i] = (fact[x + y] * inv[x] % M) * inv[y] % M;
			for (int j = 0; j < i; j++) {
				int dx = x - a[j][0];
				int dy = y - a[j][1];
				if (dx >= 0 && dy >= 0) {
					ways[i] = (ways[i] - (ways[j] * (fact[dx + dy] * inv[dx] % M)) % M * inv[dy] % M + M) % M;
				}
			}
		}

		out.println(ways[n]);
	}

	long power(long a, long b) {
		long x = 1, y = a;
		while (b > 0) {
			if (b % 2 != 0) {
				x = (x * y) % M;
			}
			y = (y * y) % M;
			b /= 2;
		}
		return x % M;
	}

	void run() throws Exception {
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);

		long s = System.currentTimeMillis();
		solve();
		out.flush();
		if (!INPUT.isEmpty())
			tr(System.currentTimeMillis() - s + "ms");
	}

	public static void main(String[] args) throws Exception {
		new Main().run();
	}

	private byte[] inbuf = new byte[1024];
	public int lenbuf = 0, ptrbuf = 0;

	private int readByte() {
		if (lenbuf == -1)
			throw new InputMismatchException();
		if (ptrbuf >= lenbuf) {
			ptrbuf = 0;
			try {
				lenbuf = is.read(inbuf);
			} catch (IOException e) {
				throw new InputMismatchException();
			}
			if (lenbuf <= 0)
				return -1;
		}
		return inbuf[ptrbuf++];
	}

	private boolean isSpaceChar(int c) {
		return !(c >= 33 && c <= 126);
	}

	private int skip() {
		int b;
		while ((b = readByte()) != -1 && isSpaceChar(b))
			;
		return b;
	}

	private double nd() {
		return Double.parseDouble(ns());
	}

	private char nc() {
		return (char) skip();
	}

	private String ns() {
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while (!(isSpaceChar(b))) { // when nextLine, (isSpaceChar(b) && b != '
									// ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}

	private char[] ns(int n) {
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while (p < n) {
			if (!(isSpaceChar(b)))
				buf[p++] = (char) b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}

	private char[][] nm(int n, int m) {
		char[][] map = new char[n][];
		for (int i = 0; i < n; i++)
			map[i] = ns(m);
		return map;
	}

	private int[] na(int n) {
		int[] a = new int[n];
		for (int i = 0; i < n; i++)
			a[i] = ni();
		return a;
	}

	private int[][] na(int n, int m) {
		int[][] a = new int[n][];
		for (int i = 0; i < n; i++)
			a[i] = na(m);
		return a;
	}

	private int ni() {
		int num = 0, b;
		boolean minus = false;
		while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
			;
		if (b == '-') {
			minus = true;
			b = readByte();
		}

		while (true) {
			if (b >= '0' && b <= '9') {
				num = num * 10 + (b - '0');
			} else {
				return minus ? -num : num;
			}
			b = readByte();
		}
	}

	private long nl() {
		long num = 0;
		int b;
		boolean minus = false;
		while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
			;
		if (b == '-') {
			minus = true;
			b = readByte();
		}

		while (true) {
			if (b >= '0' && b <= '9') {
				num = num * 10 + (b - '0');
			} else {
				return minus ? -num : num;
			}
			b = readByte();
		}
	}

	private static void tr(Object... o) {
		System.out.println(Arrays.deepToString(o));
	}
}

Measured memory_bytes: 24404