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 (h, w, n) = (c[0], c[1], c[2]);
        var map = NArr(h);
        var tree = new List<(int to, int len)>[n];
        for (var i = 0; i < tree.Length; ++i) tree[i] = new List<(int to, int len)>();
        for (var i = 0; i + 1 < n; ++i) tree[i].Add((i + 1, 0));
        for (var i = 0; i < h; ++i) for (var j = 0; j + 1 < w; ++j)
        {
            if (map[i][j] < map[i][j + 1]) tree[map[i][j] - 1].Add((map[i][j + 1] - 1, 1));
            else if (map[i][j] > map[i][j + 1]) tree[map[i][j + 1] - 1].Add((map[i][j] - 1, 1));
        }
        for (var i = 0; i + 1 < h; ++i) for (var j = 0; j < w; ++j)
        {
            if (map[i][j] < map[i + 1][j]) tree[map[i][j] - 1].Add((map[i + 1][j] - 1, 1));
            else if (map[i][j] > map[i + 1][j]) tree[map[i + 1][j] - 1].Add((map[i][j] - 1, 1));
        }
        var len = new int[n];
        for (var i = 0; i + 1 < n; ++i)
        {
            foreach (var next in tree[i])
            {
                len[next.to] = Math.Max(len[next.to], len[i] + next.len);
            }
        }
        WriteLine(new HashSet<int>(len).Count);
    }
}