#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <queue>
#include <string>
#include <map>
#include <set>
#include <stack>
#include <tuple>
#include <deque>
#include <numeric>
#include <bitset>
#include <iomanip>
#include <cassert>
#include <chrono>
#include <random>
#include <limits>
#include <iterator>
#include <functional>
#include <sstream>
#include <complex>
using namespace std;

typedef long long ll;
typedef uint64_t ull;
typedef pair<int, int> P;
constexpr double PI = 3.1415926535897932;   // acos(-1)
constexpr double EPS = 1e-9;
constexpr int INF = 1001001001;
constexpr int mod = 1000000007;
// constexpr int mod = 998244353;

#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)

template<int mod>
struct ModInt{
    int x;

    ModInt() : x(0) {}
    
    ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}
    
    ModInt &operator+=(const ModInt &p){
        if((x += p.x) >= mod)   x -= mod;
        return *this;
    }
    
    ModInt &operator-=(const ModInt &p){
        if((x += mod - p.x) >= mod) x -= mod;
        return *this;
    }

    ModInt &operator*=(const ModInt &p){
        x = (int)(1LL * x * p.x % mod);
        return *this;
    }

    ModInt &operator/=(const ModInt &p){
        *this *= p.inverse();
        return *this;
    }
    
    ModInt operator-() const {return ModInt(-x);}

    ModInt operator+(const ModInt &p) const {return ModInt(*this) += p;}

    ModInt operator-(const ModInt &p) const {return ModInt(*this) -= p;}

    ModInt operator*(const ModInt &p) const {return ModInt(*this) *= p;}

    ModInt operator/(const ModInt &p) const {return ModInt(*this) /= p;}

    bool operator==(const ModInt &p) const {return x == p.x;}

    bool operator!=(const ModInt &p) const {return x != p.x;}

    ModInt inverse() const{
        int a = x, b = mod, u = 1, v = 0, t;
        while(b > 0){
            t = a / b;
            swap(a -= t * b, b);
            swap(u -= t * v, v);
        }
        return ModInt(u);
    }

    ModInt pow(int64_t n) const{
        ModInt ret(1), mul(x);
        while(n > 0){
            if(n & 1)   ret *= mul;
            mul *= mul;
            n >>= 1;
        }
        return ret;
    }

    friend ostream &operator<<(ostream &os, const ModInt &p){
        return os << p.x;
    }

    friend istream &operator>>(istream &is, ModInt &a){
        int64_t t;
        is >> t;
        a = ModInt<mod>(t);
        return (is);
    }

    static int get_mod() {return mod;}
};

using modint = ModInt<mod>;

template<typename T>
struct Combination{
    int sz;
    vector<T> fact_;
    vector<T> ifact_;
    vector<T> inv_;
    
    Combination(int n = 1e+6) : sz(n) {
        fact_.resize(sz + 1);
        ifact_.resize(sz + 1);
        inv_.resize(sz + 1);

        fact_[0] = ifact_[sz] = inv_[0] = 1;
        for(int i = 1; i <= sz; ++i)    fact_[i] = fact_[i - 1] * i;
        ifact_[sz] /= fact_[sz];
        for(int i = sz; i > 0; --i)     ifact_[i - 1] = ifact_[i] * i;
        for(int i = 1; i <= sz; ++i)    inv_[i] = ifact_[i] * fact_[i - 1];
    }

    inline T fact(int k) const  {return fact_[k];}
    inline T ifact(int k) const {return ifact_[k];}
    inline T inv(int k) const   {return inv_[k];}

    T get_permutation(int n, int k){
        if(n < 0 || k < 0 || n < k)     return 0;
        return fact(n) * ifact(n - k);
    }

    T get_combination(int n, int k){
        if(n < 0 || k < 0 || n < k)     return 0;
        return fact(n) * ifact(k) * ifact(n - k);
    }
};

struct Data{
    int r, c;
    Data() = default;
    Data(int r, int c) : r(r), c(c) {}
    bool operator<(const Data& d) const{
        if(r == d.r)    return c < d.c;
        return r < d.r;
    }
    friend ostream& operator<<(ostream& os, const Data& d){
        return os << d.r << ' ' << d.c << '\n';
    }
    friend istream& operator>>(istream& is, Data& d){
        int x, y;
        is >> x >> y;
        d = Data(x, y);
        return is;
    }
};

// dp[i][j] := i 番目の壁を通過する通り数
// j は i 番目を通過するときに、それが偶数回目 (0) か奇数回目 (1) の壁かを表す
// 0 番目はスタート地点
modint dp[3005][2];

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int h, w, n;
    cin >> h >> w >> n;
    vector<Data> input(n);
    for(int i = 0; i < n; ++i)  cin >> input[i];
    input.push_back(Data(1, 1));
    sort(input.begin(), input.end());
    Combination<modint> comb(h + w + 5);

    dp[0][0] = 1;
    for(int i = 1; i <= n; ++i){
        int nr = input[i].r, nc = input[i].c;
        for(int j = 0; j < i; ++j){
            int r = input[j].r, c = input[j].c;
            if(nc - c < 0)  continue;
            modint route = comb.get_combination(nr - r + nc - c, nr - r);
            for(int k = 0; k < 2; ++k){
                if(dp[j][k] == 0)   continue;
                dp[i][k ^ 1] += dp[j][k] * route;
            }
        }
    }
    
    modint ban = 0;
    for(int i = 1; i <= n; ++i){
        int r = input[i].r, c = input[i].c;
        modint route = comb.get_combination(h - r + w - c, h - r);
        ban -= dp[i][0] * route;
        ban += dp[i][1] * route;
    }

    modint ans = comb.get_combination(h + w - 2, h - 1) - ban;
    cout << ans << endl;
}

Measured memory_bytes: 2816