program pr2;
  var fi,fo:text;
      a:array[1..16,1..16]of integer;
      m,n,i,j,s: integer;
begin
   assign(fi,'flip.in'); reset(fi);
   assign(fo,'flip.out'); rewrite(fo);
   s:=0;
   read(fi,n); read(fi,m);  readln(fi);
   for i:=1 to n do
     for j:=1 to m do
        read(fi,a[i,j]);
   for i:=1 to n do
     for j:=1 to m do
    if a[i,j]>0 then s:=s+a[i,j];
    write(fo,s);
   close(fi); close(fo);
end.