using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ScroogeMcDuck
{
    internal class Program
    {
        static int[][] voltMaze;
        static void Main()
        {
            int[] input = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
            int row = input[0];
            voltMaze = new int[row][];
            int startRow = 0;
            int startCol = 0;

            for (int r = 0; r < row; r++)
            {
                int[] collumns = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
                if (collumns.Contains(0))
                {
                    for (int i = 0; i < collumns.Length; i++)
                    {
                        if (collumns[i] == 0)
                        {
                            startRow = r;
                            startCol = i;
                        }
                    }
                }
                voltMaze[r] = collumns;
            }

            Console.WriteLine(GoTrueTheMaze(startRow, startCol));
        }

        private static int GoTrueTheMaze(int row, int col)
        {
            DirectionToFollow left = GetTheCoins(row, col - 1);
            DirectionToFollow right = GetTheCoins(row, col + 1);
            DirectionToFollow up = GetTheCoins(row - 1, col);
            DirectionToFollow down = GetTheCoins(row + 1, col);

            DirectionToFollow current = left;
            if (current.Coins < right.Coins)
            {
                current = right;
            }
            if (current.Coins < up.Coins)
            {
                current = up;
            }
            if (current.Coins < down.Coins)
            {
                current = down;
            }

            if (current.Coins == 0)
            {
                return 0;
            }

            voltMaze[row][col]--;

            return 1 + GoTrueTheMaze(current.Row, current.Col);

        }

        private static DirectionToFollow GetTheCoins(int row, int col)
        {
            if (IsInMaze(row, col))
            {
                return new DirectionToFollow(row, col, voltMaze[row][col]);
            }
            return new DirectionToFollow(row, col);
        }

        private static bool IsInMaze(int row, int col)
        {
            return row >= 0
                && col >= 0
                && row < voltMaze.Length
                && col < voltMaze[0].Length;
        }
    }

    public class DirectionToFollow
    {
        private const int noCoins = 0;
        public DirectionToFollow(int row, int col, int coins)
        {
            Row = row;
            Col = col;
            Coins = coins;
        }

        public DirectionToFollow(int row, int col)
            : this(row, col, noCoins)
        {}

        public int Row { get; set; }
        public int Col { get; set; }
        public int Coins { get; set; }
    }
}