#include <bits/stdc++.h>
#define fi first
#define se second
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rrep(i, n) for (int i = 1; i <= (n); ++i)
#define drep(i, n) for (int i = (n)-1; i >= 0; --i)
#define srep(i, s, t) for (int i = s; i < t; ++i)
#define rng(a) a.begin(), a.end()
#define maxs(x, y) (x = max(x, y))
#define mins(x, y) (x = min(x, y))
#define limit(x, l, r) max(l, min(x, r))
#define lims(x, l, r) (x = max(l, min(x, r)))
#define isin(x, l, r) ((l) <= (x) && (x) < (r))
#define pb push_back
#define sz(x) (int)(x).size()
#define pcnt __builtin_popcountll
#define uni(x) x.erase(unique(rng(x)), x.end())
#define snuke srand((unsigned)clock() + (unsigned)time(NULL));
#define show(x) cout << #x << " = " << x << endl;
#define PQ(T) priority_queue<T, v(T), greater<T>>
#define bn(x) ((1 << x) - 1)
#define dup(x, y) (((x) + (y)-1) / (y))
#define newline puts("")
#define v(T) vector<T>
#define vv(T) v(v(T))
using namespace std;
typedef long long int ll;
typedef unsigned uint;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<P> vp;
inline int in()
{
    int x;
    scanf("%d", &x);
    return x;
}
template <typename T>
inline istream &operator>>(istream &i, v(T) & v)
{
    rep(j, sz(v)) i >> v[j];
    return i;
}
template <typename T>
string join(const v(T) & v)
{
    stringstream s;
    rep(i, sz(v)) s << ' ' << v[i];
    return s.str().substr(1);
}
template <typename T>
inline ostream &operator<<(ostream &o, const v(T) & v)
{
    if (sz(v))
        o << join(v);
    return o;
}
template <typename T1, typename T2>
inline istream &operator>>(istream &i, pair<T1, T2> &v)
{
    return i >> v.fi >> v.se;
}
template <typename T1, typename T2>
inline ostream &operator<<(ostream &o, const pair<T1, T2> &v)
{
    return o << v.fi << "," << v.se;
}
template <typename T>
inline ll suma(const v(T) & a)
{
    ll res(0);
    for (auto &&x : a)
        res += x;
    return res;
}
const double eps = 1e-10;
const ll LINF = 1001002003004005006ll;
const int INF = 1001001001;
#define dame        \
    {               \
        puts("-1"); \
        return 0;   \
    }
#define yn           \
    {                \
        puts("YES"); \
    }                \
    else { puts("NO"); }
const int MX = 200005;

// Mod int
const int mod = 1000000007;
struct mint
{
    ll x;
    mint() : x(0) {}
    mint(ll x) : x((x % mod + mod) % mod) {}
    // mint(ll x):x(x){}
    mint &fix()
    {
        x = (x % mod + mod) % mod;
        return *this;
    }
    mint operator-() const { return mint(0) - *this; }
    mint operator~() const { return mint(1) / *this; }
    mint &operator+=(const mint &a)
    {
        if ((x += a.x) >= mod)
            x -= mod;
        return *this;
    }
    mint &operator-=(const mint &a)
    {
        if ((x += mod - a.x) >= mod)
            x -= mod;
        return *this;
    }
    mint &operator*=(const mint &a)
    {
        (x *= a.x) %= mod;
        return *this;
    }
    mint &operator/=(const mint &a)
    {
        (x *= a.ex(mod - 2).x) %= mod;
        return *this;
    }
    mint operator+(const mint &a) const { return mint(*this) += a; }
    mint operator-(const mint &a) const { return mint(*this) -= a; }
    mint operator*(const mint &a) const { return mint(*this) *= a; }
    mint operator/(const mint &a) const { return mint(*this) /= a; }
    mint ex(ll t) const
    {
        if (!t)
            return 1;
        mint res = ex(t / 2);
        res *= res;
        return (t & 1) ? res * x : res;
    }
    bool operator<(const mint &a) const { return x < a.x; }
    bool operator==(const mint &a) const { return x == a.x; }
};
mint ex(mint x, ll t) { return x.ex(t); }
istream &operator>>(istream &i, mint &a)
{
    i >> a.x;
    return i;
}
ostream &operator<<(ostream &o, const mint &a)
{
    o << a.x;
    return o;
}
typedef vector<mint> vm;
struct comb
{
    vm f, g;
    comb() {}
    comb(int mx) : f(mx + 1), g(mx + 1)
    {
        f[0] = 1;
        rrep(i, mx) f[i] = f[i - 1] * i;
        g[mx] = f[mx].ex(mod - 2);
        for (int i = mx; i > 0; i--)
            g[i - 1] = g[i] * i;
    }
    mint c(int a, int b)
    {
        if (a < b)
            return 0;
        return f[a] * g[b] * g[a - b];
    }
} c(MX);
//

int main()
{
    int h, w;
    scanf("%d%d", &h, &w);
    int n;
    scanf("%d", &n);
    vp p(n);
    cin >> p;
    p.pb(P(h, w));
    ++n;
    sort(rng(p));
    vm dp(n);
    rep(i, n)
    {
        dp[i] = c.c(p[i].fi + p[i].se - 2, p[i].fi - 1);
        rep(j, i)
        {
            int di = p[i].fi - p[j].fi;
            int dj = p[i].se - p[j].se;
            if (di >= 0 && dj >= 0)
            {
                dp[i] -= dp[j] * c.c(di + dj, di);
            }
        }
    }
    cout << dp.back() << endl;
    return 0;
}


Measured memory_bytes: 3456