from bisect import bisect_left
import sys
input = sys.stdin.readline


def lis(a: list) -> int:
    n = len(a)
    ranks = [0] * n  # ranks[i] : A[i] が LIS の何番目か
    dp = [INF] * n
    for i in range(n):
        ranks[i] = bisect_left(dp, a[i])
        dp[ranks[i]] = a[i]

    return max(ranks)+1
    # p = max(ranks)
    # res = [None] * (p+1)
    # for i in reversed(range(n)):
    #     if ranks[i] == p:
    #         res[p] = a[i]
    #         p -= 1
    #
    # return res


INF = 1 << 62
N, M, Q = map(int, input().split())

xs = []
for i in range(Q):
    A, B = map(lambda x: int(x)-1, input().split())
    xs.append((A, B))

seq = [b for _, b in sorted(xs, key=lambda x: (x[0], -x[1]))]
res = lis(seq)
print(res)