# var f,g:text;  
#     a:array[1..17,1..17] of longint;  
#     x:array[0..17] of integer;  
#     i,n,m,j,s,max,ss:longint;  
# begin  
#      assign(f,'flip.in');reset(f);  
#      assign(g,'flip.out');rewrite(g);  
#      read(f,n,m);  
#      for i:=1 to n do  
#          for j:=1 to m do  
#              begin  
#              read(f,a[i,j]);  
#              max:=max+a[i,j];  
#              end;  
#      while x[0]=0 do  
#            begin  
#                 i:=n;  
#                 while x[i]=1 do begin x[i]:=0;i:=i-1; end;  
#                 x[i]:=1;  
#                 s:=0;  
#                 for j:=1 to m do  
#                     begin  
#                          ss:=0;  
#                          for i:=1 to n do  
#                              if x[i]=1 then ss:=ss-a[i,j]  
#                                        else ss:=ss+a[i,j];  
#                          if ss<0 then ss:=-ss;  
#                          s:=s+ss;  
#                     end;  
#                 if max<s then max:=s;  
#            end;  
#      writeln(g,max);  
# close(f);  
# close(g);  
# end