from bisect import bisect_left
N, M, Q = map(int, input().split())
A = [list(map(int, input().split())) for _ in range(Q)]
A.sort(key=lambda x: (x[0], -x[1]))

INF = 10**9
dp = [INF]*(N+M+1)
dp[0] = 0

for _, b in A:
    ind = bisect_left(dp, b)
    dp[ind] = min(dp[ind], b)

ans = 0
while dp[ans+1] < INF:
    ans += 1
print(ans)