import bisect

n, m, q = map(int, input().split())
pairs = [tuple(map(int, input().split())) for _ in range(q)]
pairs.sort(key=lambda x: x[0])
ys = [b for a, b in pairs]

tails = []
for y in ys:
    idx = bisect.bisect_left(tails, y)
    if idx == len(tails):
        tails.append(y)
    else:
        tails[idx] = y

print(len(tails))