import sys
readline = sys.stdin.readline

class SegmentTree:
    def __init__(self, size, f=max, default=0):
        self.size = 2**(size-1).bit_length() 
        self.default = default
        self.dat = [default]*(self.size*2) 
        self.f = f

    def update(self, i, x):
        i += self.size
        self.dat[i] = x
        while i > 0:
            i >>= 1
            self.dat[i] = self.f(self.dat[i*2], self.dat[i*2+1])

    def query(self, l, r):
        l += self.size
        r += self.size
        lres, rres = self.default, self.default
        while l < r:
            if l & 1:
                lres = self.f(lres, self.dat[l])
                l += 1

            if r & 1:
                r -= 1
                rres = self.f(self.dat[r], rres) 
            l >>= 1
            r >>= 1
        res = self.f(lres, rres)
        return res

N, M, Q = map(int, readline().split())
D = [[] for i in range(N)]
for i in range(Q):
    A, B = map(int, readline().split())
    A, B = A - 1, B - 1
    D[A].append(B)

dp = SegmentTree(M)
for i in range(N):
    for B in sorted(D[i], reverse=True):
        val = dp.query(0, B)
        dp.update(B, val + 1)

print(dp.query(0, M))