import javax.swing.*;
import java.math.BigInteger;
import java.util.Scanner;

public class Navigation {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int r = Integer.parseInt(scan.nextLine()); // rows
        int c = Integer.parseInt(scan.nextLine()); //coloms
        int movies = Integer.parseInt(scan.nextLine());
        double[] code = new double[movies];
        for (int i = 0; i < movies; i++) {
            code[i] = scan.nextDouble();
        }
        if(r == 1 && c == 1){
            System.out.println(1);
            return;
        }
        int coff = Integer.max(r, c);

        boolean[][] matrix = new boolean[r][c];

        BigInteger sum =BigInteger.ZERO;
        BigInteger power = BigInteger.TWO;
        int pawnRow = r - 1;
        int pawnCol = 0;
        BigInteger rowPowerOfTwo;
        BigInteger colPowerofTwo;


        for (int t = 0; t < movies; t++) {
            int targetRow = (int) (code[t]) / coff;
            int targetCol = (int) (code[t]) % coff;
            if (pawnCol <= targetCol && pawnRow <= targetRow) {
                for (int col = pawnCol; col <= targetCol; col++) {
                    if (matrix[pawnRow][col]){
                        continue;
                    }
                    rowPowerOfTwo = power.pow(r - 1 - pawnRow);
                    colPowerofTwo = power.pow(col);
                    sum = sum.add(rowPowerOfTwo.multiply(colPowerofTwo));
                    matrix[pawnRow][col] = true;

                }
                pawnCol = targetCol;
                for (int row = pawnRow; row <= targetRow; row++) {
                    if (matrix[row][pawnCol]){
                        continue;
                    }
                    rowPowerOfTwo = power.pow(r  - 1 - row);
                    colPowerofTwo = power.pow(pawnCol);
                    sum = sum.add(rowPowerOfTwo.multiply(colPowerofTwo));
                    matrix[row][pawnCol] =true;
                }
                pawnRow = targetRow;
            } else if (pawnCol <= targetCol && pawnRow > targetRow) {
                for (int col = pawnCol; col <= targetCol; col++) {
                    if (matrix[pawnRow][col]){
                        continue;
                    }
                    rowPowerOfTwo = power.pow(r - 1 - pawnRow);
                    colPowerofTwo = power.pow(col);
                    sum = sum.add(rowPowerOfTwo.multiply(colPowerofTwo));
                    matrix[pawnRow][col] = true;
                }
                pawnCol = targetCol;
                for (int row = targetRow; row <= pawnRow; row++) {
                    if (matrix[row][pawnCol]){
                        continue;
                    }
                    rowPowerOfTwo = power.pow( r - 1 - row );
                    colPowerofTwo = power.pow(pawnCol);
                    sum = sum.add(rowPowerOfTwo.multiply(colPowerofTwo));
                    matrix[row][pawnCol] = true;
                }
                pawnRow = targetRow;
            } else if (pawnCol > targetCol && pawnRow <= targetRow) {
                for (int col = targetCol; col <= pawnCol; col++) {
                    if (matrix[pawnRow][col]){
                        continue;

                    }
                    rowPowerOfTwo = power.pow(r- 1 - pawnRow);
                    colPowerofTwo = power.pow(col);
                    sum = sum.add(rowPowerOfTwo.multiply(colPowerofTwo));
                    matrix[pawnRow][col] = true;
                }
                pawnCol = targetCol;
                for (int row = pawnRow; row <= targetRow; row++) {
                    if (matrix[row][pawnCol]){
                        continue;
                    }
                    rowPowerOfTwo = power.pow(r - 1 - row);
                    colPowerofTwo = power.pow(pawnCol);
                    sum = sum.add(rowPowerOfTwo.multiply(colPowerofTwo));
                    matrix[row][pawnCol] = true;
                }
                pawnRow = targetRow;

            } else {
                for (int col = targetCol; col <= pawnCol; col++) {
                    if (matrix[pawnRow][col]){
                        continue;
                    }
                    rowPowerOfTwo = power.pow(r - 1 - pawnRow);
                    colPowerofTwo = power.pow(col);
                    sum = sum.add(rowPowerOfTwo.multiply(colPowerofTwo));
                    matrix[pawnRow][col] = true;
                }
                pawnCol = targetCol;
                for (int row = targetRow; row <= pawnRow; row++) {
                    if (matrix[row][pawnCol]){
                        continue;
                    }
                    rowPowerOfTwo = power.pow( r - 1 -row);
                    colPowerofTwo = power.pow(pawnCol);
                    sum = sum.add(rowPowerOfTwo.multiply(colPowerofTwo));
                    matrix[row][pawnCol] = true;
                }
                pawnRow = targetRow;
            }


        }
        System.out.println(sum);


    }

}