mod = 1000000007
eps = 10**-9


def main():
    import sys
    from bisect import bisect_left
    input = sys.stdin.readline

    N, M, Q = map(int, input().split())
    XY = []
    for _ in range(Q):
        XY.append(tuple(map(int, input().split())))

    XY.sort(key=lambda x: x[1], reverse=True)
    XY.sort(key=lambda x: x[0])

    LIS = [0]
    for _, y in XY:
        j = bisect_left(LIS, y)
        if j == len(LIS):
            LIS.append(y)
        else:
            LIS[j] = y
    print(len(LIS) - 1)


if __name__ == '__main__':
    main()