"""

"""
from sys import stdin
import sys

N,M,Q = map(int,stdin.readline().split())

dp = [[0] * (M+1) for i in range(N+1)]

ab = set()

for i in range(Q):

    a,b = map(int,stdin.readline().split())

    ab.add((a,b))

for i in range(N+1):
    for j in range(M+1):
        dp[i][j] = max(dp[i-1][j] , dp[i][j-1])
        if (i,j) in ab:
            dp[i][j] = max(dp[i][j] , dp[i-1][j-1] + 1)

print (dp[-1][-1])