var n,m,i,x:longint;
a:array[1..1000] of longint;
tep1,tep2:text;
begin
assign(tep1,'YAL.inp'); reset(tep1);
assign(tep2,'YAL.out'); rewrite(tep2);
readln(tep1,n,m);
for i:=1 to m do
begin
read(tep1,x);
a[x]:=a[x]+1;
end;
for i:=1 to n do
if a[i]=0 then write(tep2,i,' ');
close(tep1);
close(tep2);
end.