program flip;
var  f,g:text;n,i,m,j:integer;
     a:array[1..17,1..17]of int64;s:int64;
begin
    assign(f,'flip.in');reset(f);
    assign(g,'flip.out');rewrite(g);
      readln(f,n,m);
     for i:=1 to n do begin
       for j:=1 to m do begin
        read(f,a[i,j]);
        if a[i,j]>0 then s:=s+a[i,j];
        end;
       readln(f);
       end;
       write(g,s);
     close(g);close(f);
     end.