import sys
from bisect import bisect_left

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

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

# Extract the list of b's (women indices)
ys = [b for a, b in pairs]

# Compute the LIS in O(n log n) time
tails = []
for y in ys:
    idx = bisect_left(tails, y)
    if idx == len(tails):
        tails.append(y)
    else:
        tails[idx] = y

print(len(tails))