import bisect

n, m, q = map(int, input().split())
pairs = []
for _ in range(q):
    a, b = map(int, input().split())
    pairs.append((a, b))

pairs.sort()
b_list = [b for a, b in pairs]

tails = []
for num in b_list:
    idx = bisect.bisect_left(tails, num)
    if idx < len(tails):
        tails[idx] = num
    else:
        tails.append(num)

print(len(tails))