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 by -b ascending (b descending)

pairs.sort()

# Extract the y values in the sorted order, converting back to original values
ys = [-b for a, b in pairs]

# Compute the length of the longest strictly increasing subsequence
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))