N, M, Q = map(int, input().split())
X = [[] for _ in range(N)]
for _ in range(Q):
    a, b = map(int, input().split())
    X[a-1].append(b - 1)

Y = [0] * (M + 1)
for i, x in enumerate(X):
    nY = Y[:]
    for b in x:
        nY[b+1] = max(nY[b+1], Y[b] + 1)
    Y = nY
    for i in range(M):
        Y[i+1] = max(Y[i+1], Y[i])
print(max(Y))