import java.io.*;
import java.util.*;
import java.util.stream.*;

public class Main {
    static Pair[] pairs;
    static int[][] dp;
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        int m = sc.nextInt();
        int q = sc.nextInt();
        Pair[] pairs = new Pair[q];
        for (int i = 0; i < q; i++) {
            pairs[i] = new Pair(sc.nextInt() - 1, sc.nextInt() - 1);
        }
        Arrays.sort(pairs);
        int[] dp = new int[q + 1];
        Arrays.fill(dp, Integer.MAX_VALUE);
        dp[0] = -1;
        int max = 0;
        for (Pair x : pairs) {
            int left = 0;
            int right = max + 1;
            while(right - left > 1) {
                int mm = (left + right) / 2;
                if (dp[mm] <= x.female) {
                    left = mm;
                } else {
                    right = mm;
                }
            }
            dp[right] = x.female;
            max = Math.max(max, right);
        }
        System.out.println(max);
    }

    static class Pair implements Comparable<Pair> {
        int male;
        int female;
        
        public Pair(int male, int female) {
            this.male = male;
            this.female = female;
        }
        
        public int compareTo(Pair another) {
            if (male == another.male) {
                return another.female - female;
            } else {
                return male - another.male;
            }
        }
    }
}
class Utilities {
    static String arrayToLineString(Object[] arr) {
        return Arrays.stream(arr).map(x -> x.toString()).collect(Collectors.joining("\n"));
    }
    
    static String arrayToLineString(int[] arr) {
        return String.join("\n", Arrays.stream(arr).mapToObj(String::valueOf).toArray(String[]::new));
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public int[] nextIntArray() throws Exception {
        return Stream.of(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}