#include <stdlib.h> 
#include <stdio.h> 
#include <math.h> 

struct nod{
	int data; 
	struct nod* next; 
}; 

typedef struct nod Node; 

void alocaNod(Node** head)
{
	Node* temp = (Node*)calloc(1, sizeof(Node));
	temp -> next = NULL; 
	temp -> data = 0;  
	if(*head == NULL){
		(*head) = temp; 
		return;
	}

	temp -> next = (*head); 
	*head = temp; 
	return; 
} 
 
int** doBackup(int** tabla, int n, int m)
{
	int** backup = (int**)calloc(n, sizeof(int*)); 
	int i; 
	for(i = 0; i < n; i++){
		backup[i] = (int*)calloc(m, sizeof(int)); 
	}   

	int j; 

	for(i = 0; i < n; i++){
		for(j = 0; j < m; j++){
			backup[i][j] = tabla[i][j]; 
		}
	} 

	return backup;

} 

void freeBackup(int** backup, int n)
{
	int i; 
	for(i = 0; i < n; i++){
		free(backup[i]); 
	} 

	free(backup);  
}  

int calculeaza(int** tabla, int n, int m)
{
	int s = 0; 
	int i,j; 

	for( i = 0; i < n; i++){
		for(j = 0; j < m; j++){
			s += tabla[i][j]; 
		}
	} 

	return s; 
} 

void apasaButoane(int** backup, Node* head, int n, int m)
{
	int indexParcurgere = 0; 
	int j;

	while(head != NULL){
		if(head -> data != 0){
			if(indexParcurgere < n){
				for(j = 0; j < m; j++){
					backup[indexParcurgere][j] *= (-1); 
				}
			}
			else{
				for(j = 0; j < n; j++){
					backup[j][indexParcurgere - n] *= (-1); 
				}
			}
		} 
		
			head = head -> next; 
			indexParcurgere++; 
		
	}
} 

int cmp(const void* a, const void* b)
{
	return *(int*)a - *(int*)b; 
} 

void eliberare(Node* head)
{
	if(head -> next == NULL) return; 

	 eliberare(head -> next); 

	free(head -> next); 

}

void findMax(int** tabla, int n, int m)
{
	int* sume = (int*)calloc( pow(2,(n+m)), sizeof(int)); 
	int index = 0; // contor vector sume;  
	Node* head = NULL;   
	int i;
	 

	for( i = 0; i < n + m; i++){
		alocaNod(&head); 
	} 

	int nrButoane = n + m; 

	int** backup = doBackup(tabla, n, m);
	sume[index] = calculeaza(backup, n ,m);  
	freeBackup(backup, n);

	index = 1; 

	int nrCaz = pow(2, nrButoane); 

	while( index != nrCaz){
		Node* parcurgere = head; 
		while(parcurgere -> data == 1){
			parcurgere -> data = 0; 
			parcurgere = parcurgere -> next; 
		}
		parcurgere -> data = 1; 

		//aici incepe treaba
		backup = doBackup(tabla, n , m); 
		apasaButoane(backup, head, n, m); 
		sume[index] = calculeaza(backup, n, m); 
		freeBackup(backup, n); 
		//aici se terminas
		index++;
	}

	/*for(i = 0; i < nrCaz; i++){
		printf("\n%i", sume[i]); 
	}*/ 

	qsort(sume, nrCaz, sizeof(int), cmp);  
	FILE* output = fopen("flip.out", "a"); 

	fprintf(output, "%i", sume[nrCaz - 1]); 

	eliberare(head); 
	free(head); 
	fclose(output);
	free(sume); 
	//tre sa eliberez si lista
	
}

int main()
{
	int n, m; 
	FILE* input; 

	input = fopen("flip.in", "r"); 
	 

	int i, j; 

	fscanf(input, "%i", &n); 
	fscanf(input, "%i", &m);  

	int** tabla; 
	tabla = (int**)calloc(n, sizeof(int*)); 
	
	for(i = 0; i < n; i++){
		tabla[i] = (int*)calloc(m, sizeof(int)); 
	}
	for(i = 0; i < n; i++){
		for(j = 0; j < m; j++){
			fscanf(input, "%i", &(tabla[i][j]) );
		}
	} 

	findMax(tabla, n, m);

	freeBackup(tabla, n);
	fclose(input); 
	   
	return 0;
}