from bisect import bisect_left
N,M,Q = map(int,input().split())
AB = [list(map(int,input().split())) for _ in range(Q)]
E = [[] for _ in range(M)]
for a, b in AB:
    a -= 1
    b -= 1
    E[b].append(a)

X = []
for i in range(M):
    if not E[i]:
        continue
    E[i].sort(reverse = True)
    for s in E[i]:
        if not X:
            X.append(s)
        else:
            a = bisect_left(X,s)
            if a == len(X):
                X.append(s)
            else:
                X[a] = s
print(len(X))