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

pairs.sort(key=lambda x: (x[0], x[1]))

class BIT:
    def __init__(self, size):
        self.size = size
        self.tree = [0] * (self.size + 1)  # 1-based indexing

    def update(self, idx, value):
        while idx <= self.size:
            if self.tree[idx] < value:
                self.tree[idx] = value
            else:
                break
            idx += idx & -idx

    def query(self, idx):
        res = 0
        while idx > 0:
            if self.tree[idx] > res:
                res = self.tree[idx]
            idx -= idx & -idx
        return res

bit = BIT(m)
max_dp = 0

current_a = None
group = []

for a, b in pairs:
    if a != current_a:
        if group:
            temp_dp = []
            for (a_p, b_p) in group:
                max_val = bit.query(b_p - 1)
                current_dp = max_val + 1
                temp_dp.append((b_p, current_dp))
                if current_dp > max_dp:
                    max_dp = current_dp
            for (b_p, current_dp) in temp_dp:
                if current_dp > bit.query(b_p):
                    bit.update(b_p, current_dp)
        current_a = a
        group = [(a, b)]
    else:
        group.append((a, b))

if group:
    temp_dp = []
    for (a_p, b_p) in group:
        max_val = bit.query(b_p - 1)
        current_dp = max_val + 1
        temp_dp.append((b_p, current_dp))
        if current_dp > max_dp:
            max_dp = current_dp
    for (b_p, current_dp) in temp_dp:
        if current_dp > bit.query(b_p):
            bit.update(b_p, current_dp)

print(max_dp)