#include <iostream>
using namespace std;
const int N = 30;
int n, m, k;
int f[N][N];
bool st[N][N];
int main()
{
cin >> n >> m >> k;
while (k -- )
{
int a, b;
cin >> a >> b;
st[a][b] = true;
}
f[1][1] = 1;
for (int i = 1; i <= n; i ++ )
for (int j = 1; j <= m; j ++ )
{
if (!st[i - 1][j]) f[i][j] += f[i - 1][j];
if (!st[i][j - 1]) f[i][j] += f[i][j - 1];
}
cout << f[n][m];
return 0;
}