using System;
using System.Linq;
using System.Numerics;
using System.Collections.Generic;
using System.IO;
using System.Text;
using N = System.Int32;

static class Program
{
    static public void Main(string[] args)
    {
        Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false });
        var solver = new Solver();
        solver.Solve();
        Console.Out.Flush();
    }
}

public class Solver
{
    public void Solve()
    {
        N h = rn, w = rn, m = rn;
        var bomb = new List<HashSet<N>>();
        for(int i = 0; i < h; i++)
        {
            bomb.Add(new HashSet<N>());
        }
        N[] ch = new N[h];
        N[] cw = new N[w];
        N tx = 0, ty = 0;
        for(int i = 0; i < m; i++)
        {
            tx = rn - 1;
            ty = rn - 1;
            ch[tx]++;
            cw[ty]++;
            bomb[tx].Add(ty);
        }
        N mht = 0, mwt = 0;
        for (int x = 0; x < h; x++)
        {
            if (ch[x] > mht) mht = ch[x];
        }
        for (int y = 0; y < w; y++)
        {
            if (cw[y] > mwt) mwt = cw[y];
        }
        var mh = new List<N>();
        var mw = new List<N>();
        for (int x = 0; x < h; x++)
        {
            if (ch[x] == mht) mh.Add(x);
        }
        for (int y = 0; y < w; y++)
        {
            if (cw[y] == mwt) mw.Add(y);
        }
        N d = -1;
        if (mh.Count * mw.Count > m)
        {
            d = 0;
        }
        else
        {
            for (int x = 0; x < mh.Count; x++)
            {
                if (bomb[mh[x]].Intersect(mw).Count() < mw.Count)
                {
                    d = 0;
                    break;
                }/*
                for (int y = 0; y < mw.Count; y++)
                {
                    if (!bomb[mh[x]].Contains(mw[y]))
                    {
                        d = 0;
                        x = mh.Count;
                        y = mw.Count;
                    }
                }*/
            }
        }
        Write(ch.Max() + cw.Max() + d);
    }


    N rn { get { return sc.Integer(); } }
    double rd { get { return sc.Double(); } }
    string rs { get { return sc.Scan(); } }
    public StreamScanner sc = new StreamScanner(Console.OpenStandardInput());

    void Write<T>(T t) { Console.WriteLine(t.ToString()); }
    void YN(bool t) { Console.WriteLine(t ? "YES" : "NO"); }
    void Yn(bool t) { Console.WriteLine(t ? "Yes" : "No"); }
    void yn(bool t) { Console.WriteLine(t ? "yes" : "no"); }
}



public class StreamScanner
{
    public StreamScanner(Stream stream) { str = stream; }
    private readonly Stream str;
    private readonly byte[] buf = new byte[1024];
    private int len, ptr;
    public bool isEof = false;
    public bool IsEndOfStream { get { return isEof; } }
    private byte read()
    {
        if (isEof) throw new EndOfStreamException();
        if (ptr >= len)
        {
            ptr = 0;
            if ((len = str.Read(buf, 0, 1024)) <= 0)
            {
                isEof = true;
                return 0;
            }
        }
        return buf[ptr++];
    }
    public char Char()
    {
        byte b = 0;
        do b = read();
        while (b < 33 || 126 < b);
        return (char)b;
    }
    public string Scan()
    {
        var sb = new StringBuilder();
        for (var b = Char(); b >= 33 && b <= 126; b = (char)read())
            sb.Append(b);
        return sb.ToString();
    }
    public N Integer()
    {
        N ret = 0; byte b = 0; var ng = false;
        do b = read();
        while (b != '-' && (b < '0' || '9' < b));
        if (b == '-') { ng = true; b = read(); }
        for (; true; b = read())
        {
            if (b < '0' || '9' < b)
                return ng ? -ret : ret;
            else ret = ret * 10 + b - '0';
        }
    }
    public double Double() { return double.Parse(Scan()); }
}


Measured memory_bytes: 108188