n,m,Q=map(int,input().split())
p=[[] for i in range(n)]
for i in range(Q):
	a,b=map(int,input().split())
	a-=1
	b-=1
	p[a]+=[b]
X=1<<30
q=[X]*(Q+2)
from bisect import bisect_left
for i in range(n):
	p[i].sort()
	for y in p[::-1]:
		q[bisect_left(q,y)]=y
for i in range(Q+2):
	if q[i]==X:
		print(i)
		exit()