program jocul_flip;
var f,g:text; s,i,m,n,j:integer;a:array[1..100,1..100] of integer;
begin
   assign(f,'flip.in');reset(f);
   assign(g,'flip.out');rewrite(g);
   readln(f,m,n);
   for i:=1 to m do
     begin
        for j:=1 to n do
           read(f,a[i,j]);
        readln(f);
     end;
   s:=0;
   for i:=1 to m do
     for j:=1 to n do
        if a[i,j]>0 then s:=s+a[i,j];
   writeln(g,s);
   close(f);close(g);
end.