include <bits/stdc++.h>

using namespace std; long long dp[202][202]; long long a[202]; long long b[202]; bool c[201][201];

int main() {

long long n, m, x, y;
cin >> n >> m >> x;
for (int i = 1; i <= x; i++) {
	cin >> a[i];
	cin >> b[i];
	c[a[i]][b[i]] = true;
}
dp[1][1] = 1;
c[1][1] = true;
for (int i = 1; i <= n; i++) {
	for (int j = 1; j <= m; j++) {
		if (!c[i][j]) {
			dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
		}
	}
}
cout << dp[n][m];
return 0;

}