program numere;
type matrice=array [1..10000,1..10000] of longint;
var f,g:text;
a:matrice;
m,n,i,j:integer;
s:longint;
begin
   assign(f,'flip.in');
   reset(f);
   assign(g,'flip.out');
   rewrite(g);
   readln(f,n,m);
   s:=0;
   for i:=1 to n do
      begin
         for j:=1 to m do
             read(f,a[i,j]);
      end;
   for i:=1 to n do
      begin
         for j:=1 to m do
             if a[i,j]>0 then
                  s:=s+a[i,j]
      end;
   writeln(g,s);
   close(f);
   close(g);
end.