#include <stdio.h>
#include <limits.h>



int N, M, sumMax, currentSum;
int table[16][16];


unsigned int power(unsigned int base, unsigned int exp)
{
    register unsigned int result = 1;
    for (;;)
    {
        if (exp & 1)
            result *= base;
        exp >>= 1;
        if (!exp)
            break;
        base *= base;
    }

    return result;
}


inline int computeSum(unsigned int rowsFlip, unsigned int colsFlip)
{
    register int i, j, sum = 0, minusOn;
    //printf("rowsflip=%x, colsFlip=%x\n", rowsFlip, colsFlip);
    for (i = 0; i < N; i++)
    {
        for (j = 0; j < M; j++)
        {
            minusOn = (((rowsFlip >> i) & 0x01) + ((colsFlip >> j) & 0x01)) % 2;
            if (minusOn)
            {
                sum -= table[i][j];
            }
            else
            {
                sum += table[i][j];
            }

        }
    }
    return sum;
}

void printMatrix(void)
{
    int i, j;
    for (i = 0; i < N; i++)
    {
        for (j = 0; j < M; j++)
        {
            printf("%d ", table[i][j]);
        }
        printf("\n");
    }
    printf("printing finished\n");
}

void readInput(void)
{
    register int i, j;
    FILE * fp;
    fp = fopen("flip.in", "r");
    if (!fscanf(fp, "%d", &N))
    {
        fclose(fp);
        return;
    }
    if (!fscanf(fp, "%d", &M))
    {
        fclose(fp);
        return;
    }
    for (i = 0; i < N; i++)
    {
        for (j = 0; j < M; j++)
        {
            if (!fscanf(fp, "%d", &table[i][j]))
            {
                fclose(fp);
                return;
            }
        }
    }
    fclose(fp);
}

inline void iterateThroughSolutions(void)
{
    register unsigned int i, j;

    for (i = 0; i < power(2, N - 1); i++)
    {
        for (j = 0; j < power(2, M); j++)
        {
            currentSum = computeSum(i,j);
            (currentSum > sumMax ? sumMax = currentSum: 1);
            /*if (currentSum > sumMax)
            {
                sumMax = currentSum;
            }*/
        }
    }
}

void printOutput(void)
{
    FILE * fp;
    fp = fopen("flip.out", "w");
    fprintf(fp, "%d", sumMax);
    fclose(fp);
}

int main(void)
{
    sumMax = INT_MIN;
    currentSum = INT_MIN;
    readInput();

    iterateThroughSolutions();

    printOutput();

    return 0;
}