水题，直接模拟即可
program translate;
var
q:array[1..1000] of integer;
a:array[1..1000] of boolean;
ans,n,m,i,x,head,tail:integer;
begin
assign(input,'translate.in');
reset(input);
assign(output,'translate.out');
rewrite(output);
fillchar(a,sizeof(a),false);
readln(n,m);
ans:=0;
head:=1;
tail:=0;
for i:=1 to m do
begin
read(x);
if a[x] then continue;
if tail-head+1=n then
begin
a[q[head]]:=false;
inc(head);
end;
if not a[x] then
begin
a[x]:=true;
inc(ans);
inc(tail);
q[tail]:=x;
end;
end;
readln;
writeln(ans);
close(input);
close(output);
end.
