program elimin;
 type vect = array[1..7294] of integer;
 var a,b: vect;
     i,j,i2,j2,k: integer;
     max: longword;
     m,n,r,c: byte;
     f: text;
 begin
   assign(f,'elimin.in'); reset(f);
      read(f,m,n,r,c);

      for i:=1 to m*n do
         read(f,a[i]);

   Close(f);

   for i2:=1 to m do
     for j2:=1 to n do begin

        for k:=1 to m*n do begin

          j:= k mod n;
          i:= k div n + 1;
          if j = 0 then begin
            j:=n;
            dec(i);
          end;

          if (i<>i2) and (j<>j2) then

            inc(b[(i2-1)*n + j2],a[k]);

        end;

     end;

   max := b[1];
   for i:=2 to m*n do begin

     if b[i] > max then max := b[i];

   end;

   assign(f,'elimin.out'); rewrite(f);

     write(f,max);

   Close(f);

 end.