from sys import stdin
import bisect
n, m, q, *indata = map(int, stdin.read().split())
offset = 0
hq = []
for i in range(q):
    s, t = indata[offset + 2*i],indata[offset + 2*i+1]
    hq.append((s,-t))

hq.sort()
dp = [-hq[0][1]]
ans = 1
for i in range(1,q):
    a = -hq[i][1]
    kari = bisect.bisect_left(dp,a)
    if kari == ans:
        dp.append(a)
        ans += 1
    else:
        dp[kari] = a
print("{}".format(ans))