N,M,Q = map(int,input().split())
dat = [[0] * (M+1) for _ in range(N + 1)]

for _ in range(Q):
    a,b = map(int,input().split())
    dat[a][b] = 1
    
dp = [[0] * (M + 1) for _ in range(N + 1)]
for i in range(1,N + 1):
    for j in range(1,M + 1):
        dp[i][j] = max(dp[i-1][j],dp[i][j-1],dp[i-1][j-1] + dat[i][j])
print(dp[N][M])