N, M, Q = map(int, input().split())
A = [[0]*(M+1) for _ in range(N+1)]
for _ in range(Q):
    a, b = map(int, input().split())
    A[a][b] = 1

dp = [[0]*(M+1) for _ in range(N+1)]
for i in range(1, N+1):
    for j in range(1, M+1):
        if A[i][j]:
            dp[i][j] = dp[i-1][j-1]+1
        else:
            dp[i][j] = max(dp[i-1][j], dp[i][j-1])

print(dp[N][M])