BitShiftMatrix

import java.math.BigInteger;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int R = scanner.nextInt();
        int C = scanner.nextInt();
        int N = scanner.nextInt();
        int[] moves = new int[N];


        BigInteger[][] matrix = new BigInteger[R][C];


        BigInteger startValue = new BigInteger("1");
        for (int row = R -1; row >= 0; row--) {
            for (int col = 0; col < C; col++) {
                matrix[row][col] = startValue;
                if (col < C - 1) {
                    startValue = startValue.multiply(BigInteger.valueOf(2));
                }
            }
            startValue = matrix[row][1];
        }


//        for (int i = R - 1; i >= 0 ; i--) {
//            for (int j = 0; j < C; j++) {
//                System.out.print( matrix[i][j] + " ");
//            }
//            System.out.println();
//        }


        int[] rowDirections = new int[moves.length];
        int[] colDirections = new int[moves.length];
        int COEF = Math.max(R,C);


        for (int i = 0; i < moves.length; i++) {
            moves[i] = scanner.nextInt();
        }
        int startRow = matrix.length - 1;
        int startCol = 0;
        BigInteger sum = matrix[startRow][startCol];
        matrix[startRow][startCol] = BigInteger.valueOf(0);




        for (int i = 0; i < moves.length; i++) {
            if (i == 0) {
                rowDirections[i] = (moves[i] / COEF) - startRow;
                colDirections[i] = moves[i] % COEF;
            } else {
                rowDirections[i] = moves[i] / COEF - moves[i - 1] / COEF;
                colDirections[i] = moves[i] % COEF - moves[i - 1] % COEF;
            }
        }

            for (int i = 0; i < N; i++) {
                if (colDirections[i] > 0) {
                    for (int j = 0; j < colDirections[i]; j++) {
                        startCol++;
                        sum = sum.add(matrix[startRow][startCol]);
                        matrix[startRow][startCol] = BigInteger.valueOf(0);
                    }
                } else if (colDirections[i] < 0) {
                    for (int j = 0; j > colDirections[i]; j--) {
                        startCol--;
                        sum = sum.add(matrix[startRow][startCol]);
                        matrix[startRow][startCol] = BigInteger.valueOf(0);
                    }
                }
                if (rowDirections[i] > 0) {
                    for (int j = 0; j < rowDirections[i]; j++) {
                        startRow++;
                        sum = sum.add(matrix[startRow][startCol]);
                        matrix[startRow][startCol] = BigInteger.valueOf(0);
                    }
                } else if (rowDirections[i] < 0) {
                    for (int j = 0; j > rowDirections[i]; j--) {
                        startRow--;
                        sum = sum.add(matrix[startRow][startCol]);
                        matrix[startRow][startCol] = BigInteger.valueOf(0);
                    }
                }




        }
        System.out.println(sum);
    }
}