n, m, q = map(int, input().split())
ab = [list(map(int, input().split())) for i in range(q)]
ab.sort(key=lambda x: (x[0], -x[1]))
INF = 10 ** 9
from bisect import bisect_left
dp = [INF] * (q + 1)
for a, b in ab:
    dp[bisect_left(dp, b)] = b
print(bisect_left(dp, INF))