using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (n, m, q) = (c[0], c[1], c[2]);
        var map = NArr(q);
        var ex = new bool[n, m];
        foreach (var pair in map) ex[pair[0] - 1, pair[1] - 1] = true;
        var seg = new SegmentTree<int>(m, new SegOp());
        for (var i = 0; i < n; ++i) for (var j = 0; j < m; ++j) if (ex[i, j])
        {
            if (j == 0) seg[j] = 1;
            else seg[j] = seg.Prod(0, j) + 1;
        }
        WriteLine(seg.Prod(0, m));
    }
    struct SegOp : ISegmentTreeOperator<int>
    {
        public int Identity => 0;
        public int Operate(int x, int y)
        {
            return Math.Max(x, y);
        }
    }
    interface ISegmentTreeOperator<T>
    {
        T Identity { get; }
        T Operate(T x, T y);
    }
    class SegmentTree<T>
    {
        int size;
        int log;
        T[] d;
        ISegmentTreeOperator<T> op;
        void Update(int k)
        {
            d[k] = op.Operate(d[2 * k], d[2 * k + 1]);
        }
        public SegmentTree(int n, ISegmentTreeOperator<T> op)
        {
            this.op = op;
            size = 1;
            while (size < n) size <<= 1;
            log = CountRZero(size);
            d = new T[2 * size];
            for (var i = 0; i < d.Length; ++i) d[i] = op.Identity;
        }
        public SegmentTree(T[] v, ISegmentTreeOperator<T> op)
        {
            this.op = op;
            size = 1;
            while (size < v.Length) size <<= 1;
            log = CountRZero(size);
            d = new T[2 * size];
            for (var i = 0; i < size; ++i) d[i] = op.Identity;
            for (var i = 0; i < v.Length; ++i) d[size + i] = v[i];
            for (var i = size - 1; i >= 1; --i) Update(i);
        }
        int CountRZero(int n)
        {
            var ans = 0;
            while (n % 2 == 0)
            {
                ++ans;
                n >>= 1;
            }
            return ans;
        }
        public T this[int p]
        {
            get { return d[p + size]; }
            set
            {
                p += size;
                d[p] = value;
                for (var i = 1; i <= log; ++i) Update(p >> i);
            }
        }
        public T Prod(int l, int r)
        {
            var sml = op.Identity;
            var smr = op.Identity;
            l += size;
            r += size;
            while (l < r)
            {
                if ((l & 1) != 0) sml = op.Operate(sml, d[l++]);
                if ((r & 1) != 0) smr = op.Operate(d[--r], smr);
                l >>= 1;
                r >>= 1;
            }
            return op.Operate(sml, smr);
        }
        T AllProd() => d[1];
        int MinLeft(int r, Predicate<T> f)
        {
            if (r == 0) return 0;
            r += size;
            T sm = op.Identity;
            do
            {
                r--;
                while (r > 1 && (r % 2) != 0) r >>= 1;
                if (!f(op.Operate(d[r], sm)))
                {
                    while (r < size)
                    {
                        r = 2 * r + 1;
                        if (f(op.Operate(d[r], sm)))
                        {
                            sm = op.Operate(d[r], sm);
                            r--;
                        }
                    }
                    return r + 1 - size;
                }
                sm = op.Operate(d[r], sm);
            }
            while ((r & -r) != r);
            return 0;
        }
    }
}