import sys
#input = sys.stdin.readline
input = sys.stdin.buffer.readline
from collections import defaultdict 

class SegmentTree(object):
    def __init__(self, A, dot, unit):
        n = 1 << (len(A) - 1).bit_length()
        tree = [unit] * (2 * n)
        for i, v in enumerate(A):
            tree[i + n] = v
        for i in range(n - 1, 0, -1):
            tree[i] = dot(tree[i << 1], tree[i << 1 | 1])
        self._n = n
        self._tree = tree
        self._dot = dot
        self._unit = unit

    def __getitem__(self, i):
        return self._tree[i + self._n]

    def update(self, i, v):
        i += self._n
        self._tree[i] = v
        while i != 1:
            i >>= 1
            self._tree[i] = self._dot(self._tree[i << 1], self._tree[i << 1 | 1])

    def add(self, i, v):
        self.update(i, self[i] + v)

    def sum(self, l, r): #これで[l,r)から取り出す。
        l += self._n
        r += self._n
        l_val = r_val = self._unit
        while l < r:
            if l & 1:
                l_val = self._dot(l_val, self._tree[l])
                l += 1
            if r & 1:
                r -= 1
                r_val = self._dot(self._tree[r], r_val)
            l >>= 1
            r >>= 1
        return self._dot(l_val, r_val)

def main():
    N,M,Q = map(int,input().split())
    G = [[] for _ in range(Q)]
    #L = []
    dic = defaultdict(list)
    for i in range(Q):
        a,b = map(int,input().split())
        #a -= 1; b -= 1
        #L.append((a,b)) #man,woman,index
        dic[a].append(b)
    #print(dic)
    KEY = list(dic.keys())
    KEY.sort()
    Tree = SegmentTree([0]*(M+1),max,0) #womanがyの時の最大値
    for x in KEY:
        L = sorted(dic[x])
        #print(L)
        val = []
        #if len(L) == 0: continue
        for y in L:
            temp = max(Tree.sum(0,y) + 1, Tree.__getitem__(y))
            #print(val)
            val.append(temp)
        for i in range(len(val)):
            y = L[i]
            v = val[i]
            Tree.update(y,v)
    ans = 0
    for i in range(M+1):
        ans = max(ans,Tree.__getitem__(i))
    print(ans)
        

if __name__ == '__main__':
    main()