import bisect
import sys
readline=sys.stdin.readline

def LIS(lst,weakly=False,max_value=float('inf')):
    f=bisect.bisect_right if weakly else bisect.bisect_left
    N=len(lst)
    update=[None]*N
    dp=[max_value]*N
    for k,x in enumerate(lst):
        i=f(dp,x)
        dp[i]=x
        update[k]=(i,dp[i])
    n=bisect.bisect_left(dp,max_value)
    lis=[None]*n
    n-=1
    for i,x in update[::-1]:
        if i==n:
            lis[n]=x
            n-=1
    return lis

N,M,Q=map(int,readline().split())
AB=[]
for _ in range(Q):
    a,b=map(int,readline().split())
    AB.append((a,b))
AB.sort(key=lambda tpl:(tpl[0],-tpl[1]))
B=[b for a,b in AB]
inf=1<<60
ans=len(LIS(B,max_value=inf))
print(ans)