import sys

input = sys.stdin.buffer.readline

N, M, Q = map(int, input().split())

matr = [[False] * M for _ in range(N)]
for _ in range(Q):
    a, b = (int(x) - 1 for x in input().split())
    matr[a][b] = True

dp = [[0] * (M + 1) for _ in range(N + 1)]
for a in range(N):
    for b in range(M):
        if matr[a][b]:
            dp[a + 1][b + 1] = max(dp[a][b] + 1, dp[a + 1][b], dp[a][b + 1])
        else:
            dp[a + 1][b + 1] = max(dp[a + 1][b], dp[a][b + 1])
print(dp[-1][-1])