var dem:array[0..100000] of longint;
i,n,a,cnt:longint;
f1,f2:text;
begin
assign(f1,'KT.INP');
assign(f2,'KT.OUT');
reset(f1);rewrite(f2);
readln(f1,n);
for i:=1 to n do
begin
read(f1,a);
inc(dem[a]);
if dem[a] = 2 then inc(cnt);
end;
writeln(f2,cnt);
close(f1);close(f2);
end.