from collections import defaultdict, deque

UD = 0 # Up-Down, lamp is vertical
LR = 1 # Left-Right, lamp is horizontal

n, r, k = map(int,input().split()) 
idxToPt = defaultdict(tuple)
for i in range(k):
    ptX, ptY = map(int, input().split())
    idxToPt[i + 1] = (ptX, ptY)
g1 = {i: [] for i in range(1, k + 1)}
g2 = {i: [] for i in range(1, k + 1)}

for i in range(1, k + 1):
    for j in range(i + 1, k + 1):
        x1, y1 = idxToPt[i]
        x2, y2 = idxToPt[j]
        # same x coordinate: check y coordinate for UD conflict
        if x1 == x2:
            if abs(y1 - y2) <= 2 * r:
                g1[i].append(j)
                g1[j].append(i)
        if y1 == y2: # same y coordinate: check x coordinate for LR conflict
            if abs(x1 - x2) <= 2 * r:
                g2[i].append(j)
                g2[j].append(i)

def bfs(start):
    color[start] = 0
    q = deque([start])
    while q:
        current = q.popleft()
        # assert color[current] != -1 # will cause runtime error if false
        if color[current] == UD:
            for neighbor in g1[current]:
                if color[neighbor] == -1:
                    color[neighbor] = LR # 1 - color[current] also works
                    q.append(neighbor)
                elif color[neighbor] == UD: # can't have both UD in graph 
                    return False
        else: # color[current] is 1
            for neighbor in g2[current]:
                if color[neighbor] == -1:
                    color[neighbor] = UD
                    q.append(neighbor)
                elif color[neighbor] == LR: # can't have both LR in graph 2
                    # print(current, neighbor)
                    return False
    return True

color = [-1] * (k + 1)
for i in range(1, k + 1):
    if color[i] == -1:
        res = bfs(i)
        if not res:
            # print(color)
            print(0)
            exit()
print(1)