N,M,Q = map(int,input().split()) lsAB = [set() for i in range(N+1)] for i in range(Q): a,b = map(int,input().split()) lsAB[a].add(b) dp = [[0]*(M+1) for i in range(N+1)] for i in range(1,N+1): for j in range(1,M+1): if j in lsAB[i]: dp[i][j] = max(dp[i-1][j]+1,dp[i][j-1]) else: dp[i][j] = max(dp[i-1][j],dp[i][j-1]) print(dp[-1][-1])