N,M,Q=map(int,input().split())

E=[set() for i in range(N+1)]

for i in range(Q):
    a,b=map(int,input().split())
    E[a].add(b)

DP=[0]*(M+1)

for i in range(N+1):
    NDP=[0]*(M+1)

    for j in range(1,M+1):
        NDP[j]=DP[j]
        if j in E[i]:
            NDP[j]=max(NDP[j],DP[j-1]+1)

    DP=NDP
    for j in range(1,M+1):
        DP[j]=max(DP[j-1],DP[j])

    #print(DP)

print(max(DP))