import java.io.PrintWriter
import java.util.*
import kotlin.math.*

fun PrintWriter.solve() {
    val n = nextInt()
    val m = nextInt()
    val q = nextInt()
    val adj = Array(q) { mutableListOf<Int>() }
    val data = Array(q) { nextInt() to nextInt() }
    for (i in 0 until q) {
        for (j in 0 until q) {
            if (data[i].first < data[j].first && data[i].second < data[j].second) {
                adj[i].add(j)
            }
        }
    }
    val dp = IntArray(q) { -1 }
    fun dfs(v: Int): Int {
        if (dp[v] != -1) return dp[v]
        var max = 0
        for (w in adj[v]) {
            max = maxOf(max, dfs(w))
        }
        dp[v] = max + 1
        return dp[v]
    }
    (0 until q).forEach { dfs(it) }
    println(dp.maxOrNull())
}

fun main() {
    Thread(null, {
        val writer = PrintWriter(System.out, false)
        writer.solve()
        writer.flush()
    }, "solve", 1.shl(26))
        .apply { setUncaughtExceptionHandler { _, e -> e.printStackTrace(); kotlin.system.exitProcess(1) } }
        .apply { start() }.join()
}

// region Scanner
private var st = StringTokenizer("")
private val br = System.`in`.bufferedReader()

fun next(): String {
    while (!st.hasMoreTokens()) st = StringTokenizer(br.readLine())
    return st.nextToken()
}

fun nextInt() = next().toInt()
fun nextLong() = next().toLong()
fun nextLine() = br.readLine()
fun nextDouble() = next().toDouble()
// endregion