import bisect

n, m, q = map(int, input().split())
pairs = []
for _ in range(q):
    a, b = map(int, input().split())
    pairs.append((a, b))

# Sort by a ascending, then b descending to handle same a's correctly
pairs.sort(key=lambda x: (x[0], -x[1]))

# Extract the list of y's (b values) in the sorted order
ys = [b for a, b in pairs]

# Compute the longest strictly increasing subsequence using binary search
tails = []
for y in ys:
    idx = bisect.bisect_left(tails, y)
    if idx == len(tails):
        tails.append(y)
    else:
        tails[idx] = y

print(len(tails))