from bisect import bisect_left

n, m, q = map(int, input().split())
lst = [[] for _ in range(n)]
for _ in range(q):
    x, y = map(int, input().split())
    lst[x - 1].append(y)
Y = []
for ls in lst:
    ls.sort(reverse = True)
    Y += ls

lst = []
for y in Y:
    p = bisect_left(lst, y)
    if p == len(lst):
        lst.append(y)
    else:
        lst[p] = y

print(len(lst))