#include <bits/stdc++.h>
#define maxN 1002
#define maxV 2000002
#define mod 2000003
using namespace std;
int n, m, c, ans, dp[maxN], f[maxV];
struct coord
{
    int x, y;
} v[maxN];
int invmod(int x)
{
    int i, p = mod - 2, ans = 1, aux = x;
    for (i = 1; i <= p; i <<= 1)
    {
        if(i & p)
            ans = (1LL * ans * aux) % mod;
        aux = (1LL * aux * aux) % mod;
    }
    return ans;
}
int C(int x, int y, int z, int t)
{
    ans = f[abs(x - z) + abs(y - t)];
    ans = (1LL * ans * invmod(f[abs(x - z)])) % mod;
    ans = (1LL * ans * invmod(f[abs(y - t)])) % mod;
    return ans;
}
int cmp(const coord a, const coord b)
{
    if (a.x == b.x)
        return a.y < b.y;
    return a.x < b.x;
}
void read()
{
    int i;
    freopen("padure2.in", "r", stdin);
    scanf("%d %d", &n, &m);
    scanf("%d", &c);
    for (i = 1; i <= c; ++ i)
        scanf("%d %d", &v[i].x, &v[i].y);
    f[0] = 1;
    for (i = 1; i <= n + m; ++ i)
        f[i] = (1LL * f[i - 1] * i) % mod;
}
void solve()
{
    int i, j;
    sort(v + 1, v + c + 1, cmp);
    v[0].x = v[0].y = 1;
    for(i = c; i >= 0; -- i)
    {
        dp[i] = C(n, m, v[i].x, v[i].y);
        for(j = i + 1; j <= c; ++ j)
        {
            if (v[i].y <= v[j].y)
            {
                dp[i] = dp[i] - (1LL * C(v[i].x, v[i].y, v[j].x, v[j].y) * dp[j]) % mod;
                if (dp[i] < 0)
                    dp[i] += mod;
            }
        }
    }
    ans = dp[0];
}
void write()
{
    freopen("padure2.out", "w", stdout);
    printf("%d\n", ans);
}
int main()
{
    read();
    solve();
    write();
    return 0;
}