#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define F first
#define S second
#define pii pair<int, int>
#define eb emplace_back
#define all(v) v.begin(), v.end()
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep3(i, l, n) for (int i = l; i < (n); ++i)
#define sz(v) (int)v.size()
const int inf = 1e9 + 7;
const ll INF = 1e18;
const int mod = 1000000007;
#define abs(x) (x >= 0 ? x : -(x))
#define lb(v, x) (int)(lower_bound(all(v), x) - v.begin())
#define ub(v, x) (int)(upper_bound(all(v), x) - v.begin())
template<typename T1, typename T2> inline bool chmin(T1 &a, T2 b) { if (a > b) { a = b; return 1; } return 0; }
template<typename T1, typename T2> inline bool chmax(T1 &a, T2 b) { if (a < b) { a = b; return 1; } return 0; }
template<typename T> T gcd(T a, T b) { if (b == 0) return a; return gcd(b, a % b); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
template<typename T> T pow(T a, int b) { return b ? pow(a * a, b / 2) * (b % 2 ? a : 1) : 1; }
ll modpow(ll a, int b, int _mod) { return b ? modpow(a * a % _mod, b / 2, _mod) * (b % 2 ? a : 1) % _mod : 1; }
template<class T> ostream& operator<<(ostream& os, const vector<T>& vec) { for (auto &vi: vec) os << vi << " "; return os; }
template<class T, class U> ostream& operator<<(ostream& os, const pair<T, U>& p) { os << p.F << " " << p.S; return os; }
template<class T> inline void add(T &a, int b) { a += b; if (a >= mod) a -= mod; }



void solve();

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cout << fixed << setprecision(10);

    int T;
    // cin >> T;
    T = 1;

    while (T--) {
        solve();
    }
}

const int MAX = 2000005;
ll fac[MAX], finv[MAX], inv[MAX];
// テーブルを作る前処理
void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % mod;
        inv[i] = mod - inv[mod % i] * (mod / i) % mod;
        finv[i] = finv[i - 1] * inv[i] % mod;
    }
}
// 二項係数計算
ll COM(int n, int k) {
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % mod) % mod;
}

void solve() {
  int h, w, n;
  cin >> h >> w >> n;
  vector<pii> v(n);
  rep(i, n) cin >> v[i].F >> v[i].S;
  sort(all(v));
  // rep(i, n) cout << v[i].F << " " << v[i].S << endl;

  vector<ll> dp(n); // 壁のなかで, 壁 i に最初にぶつかる場合の数
  COMinit();
  rep(i, n) {
    int Ri = v[i].F, Ci = v[i].S;
     dp[i] = COM((Ri - 1) + (Ci - 1), Ri - 1);

     // i-1 番目までの壁を避けないと
     // 余事象
     rep(j, i) {
       int Rj = v[j].F, Cj = v[j].S;
       if (Rj > Ri || Cj > Ci) continue; // j が i の左上
       // 壁 j で初めてぶつかる
       (dp[i] += mod - dp[j] * COM((Ri - Rj) + (Ci - Cj), Ri - Rj) % mod) %= mod;
     }
  }

  rep(i, n) {
    int R = v[i].F, C = v[i].S;
    (dp[i] *= COM(h - R + w - C, h - R)) %= mod;
  }

  ll ans = COM(h - 1 + w - 1, h - 1);
  // 余事象だから
  rep(i, n) (ans += mod - dp[i]) %= mod;
  cout << ans << endl;
}

void solve2() {
  int h, w, n;
  cin >> h >> w >> n;
  int table[h][w];
  fill_n(*table, h * w, 0);
  rep(i, n) {
    int y, x;
    cin >> y >> x;
    y--; x--;
    table[y][x] = 1;
  }
  int dp[h][w];
  fill_n(*dp, h * w, 0);
  dp[0][0] = 1;
  rep(i, h) rep(j, w) {
    if (table[i][j] == 0) {
      if (i && table[i - 1][j] == 0) dp[i][j] += dp[i - 1][j];
      if (j && table[i][j - 1] == 0) dp[i][j] += dp[i][j - 1];
    }
  }
  rep(i, h) { rep(j, w) cout << dp[i][j] << " "; cout << endl; }
}


Measured memory_bytes: 47232