#include<bits/stdc++.h>
#define FILE "read"
#define N 200000
using namespace std;
typedef long long ll;
const ll mod=(ll)1e9+7;
struct node{ll x,y;}p[2010];
ll n,m,k,f[2010],inv[N+50],fac[N+50];
inline ll read(){
	ll x=0,f=1;  char ch=getchar();
	while(!isdigit(ch))  {if(ch=='-')  f=-1;  ch=getchar();}
	while(isdigit(ch))  {x=x*10+ch-'0';  ch=getchar();}
	return x*f;
}
bool cmp(node a,node b){return a.x==b.x?a.y<b.y:a.x<b.x;}
ll fast(ll a,ll b){ll ret(1);for(;b;b>>=1,a=a*a%mod)if(b&1)ret=ret*a%mod;return ret;}
ll C(ll n,ll m){return fac[n]*inv[m]%mod*inv[n-m]%mod;}
void pre(){
	fac[0]=1; for(ll i=1;i<=N;++i) fac[i]=fac[i-1]*i%mod;
	inv[N]=fast(fac[N],mod-2);
	for(ll i=N-1;i>=0;--i)  inv[i]=inv[i+1]*(i+1)%mod;
}
int main(){
	freopen(FILE".in","r",stdin);
	freopen(FILE".out","w",stdout);
	n=read()-1;  m=read()-1;  k=read();  pre();
	for(ll i=1;i<=k;++i)  p[i].x=read()-1,p[i].y=read()-1;
	p[++k].x=n;  p[k].y=m;
	sort(p+1,p+k+1,cmp);
	for(ll i=1;i<=k;++i){
		f[i]=C(p[i].x+p[i].y,p[i].x);
		for(ll j=1;j<i;++j)
			if(p[i].y>=p[j].y) (f[i]-=f[j]*C(p[i].x+p[i].y-p[j].x-p[j].y,p[i].x-p[j].x)%mod)%=mod;
	}
	printf("%lld\n",(f[k]+mod)%mod);
	return 0;
}