Pesho&2

using System;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using System.Threading.Tasks;

namespace _03
{
    class Program
    {

        static void Main(string[] args)
        {
            int r = int.Parse(Console.ReadLine());
            int c = int.Parse(Console.ReadLine());
            int n = int.Parse(Console.ReadLine());
            decimal[] commands = Console.ReadLine().Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries).Select(x => decimal.Parse(x)).ToArray();
            BigInteger sum = 0;
            BigInteger[,] matrix = new BigInteger[r, c];
            BigInteger power = 1;
            for (int row = r - 1; row >= 0; row--)
            {
                for (int col = 0; col < c; col++)
                {
                    matrix[row, col] = (BigInteger)((BigInteger)Math.Pow(2, col) * power);
                }
                power = power * 2;
            }
            int peshoRow = r - 1;
            int peshoCol = 0;

            string direction = "";
            switch (direction)
            {
                case "up": peshoRow--;
                    break;
                case "down": peshoRow++;
                    break;
                case "left": peshoCol--;
                    break;
                case "right": peshoCol++;
                    break;
            }

            foreach (var command in commands)
            {
                int coeff = Math.Max(r, c);
                decimal targetRow = (ulong)(command / coeff);
                decimal targetCol = (ulong)(command % coeff);

                while (targetRow != peshoRow && peshoRow >= 0 && peshoRow < r && peshoCol < c && peshoCol >= 0)
                {
                    if (targetRow < peshoRow) peshoRow--;//direction = "up";
                    else if (targetRow > peshoRow) peshoRow++;//direction = "down";
                    sum += matrix[peshoRow, peshoCol];
                    matrix[peshoRow, peshoCol] = 0;

                }
                while (targetCol != peshoCol && peshoRow >= 0 && peshoRow < r && peshoCol < c && peshoCol >= 0)
                {
                    if (targetCol < peshoCol) peshoCol--;
                    else if (targetCol > peshoCol) peshoCol++;
                    sum += matrix[peshoRow, peshoCol];
                    matrix[peshoRow, peshoCol] = 0;
                }
            }

            Console.WriteLine(sum + 1);
        }
    }
}