#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <cstdio>
#include <set>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)

const int INF = 1e9;
int p, q, n;
int x[100001], y[100001];

int main(void){
	cin >> p >> q >> n;
	int lx = INF, rx = -INF, uy = -INF, sy = INF;
	rep(i, n){
		cin >> x[i] >> y[i];
		lx = min(lx, x[i]);//左端
		rx = max(rx, x[i]);//右端
		uy = max(uy, y[i]);//上
		sy = min(sy, y[i]);//下
	}
	int dx[] = {p, p, -p, -p, q, q, -q, -q};
	int dy[] = {q, -q, q, -q, p, -p, p, -p};

	set<pair<int, int> > s;
	queue<pair<int, int> > q;
	q.push(make_pair(0, 0));
	while(!q.empty()){
		auto now = q.front(); q.pop();
		// printf("k %d %d\n", now.first, now.second);
		rep(i, 8){
			int ny = now.first + dy[i], nx = now.second + dx[i];
			if(!(lx <= nx && nx <= rx && sy <= ny && ny <= uy)) continue;
			if(s.count(make_pair(ny, nx)) != 0) continue;
			// printf("%d %d\n", nx, ny);
			s.insert(make_pair(ny, nx));
			q.push(make_pair(ny, nx));
		}
	}

	int ret = 0;
	rep(i, n){
		if(s.count(make_pair(y[i], x[i])) != 0){
			ret++;
		}
	}
	printf("%d\n", ret);
}