I have WA 10, but I can't find my mistake, it seems that my program works very well :(
help me please

var
a : array[0..100005] of integer;
b : array[0..100005] of word;
c : array[0..1005] of integer;
x,y,i,m,n,d : integer;
cc,p : char;
begin
  assign(input,'input.txt'); reset(input);
  assign(output,'output.txt'); rewrite(output);
    readln(n); m := 0; i := 0;
    while i < n do
    begin
      read(cc);
      d := 0;
      while (not (cc in ['A'..'Z'])) do
      begin
        if EOLN then
        begin
         d := 1;
         break;
        end;
        read(cc);
      end;
      if d = 1 then begin readln;continue; end;




      if cc <> 'P' then
      begin
        readln;
        continue;
      end;
            inc(i);
      read(cc);

      p := cc;
      while p in ['P','U','S','H','O'] do read(p);

      if cc = 'U' then
      begin
        readln(x,y);
        inc(m);
        a[m] := y;
        b[m] := c[x];
        c[x] := m;

      end else
      if cc = 'O' then
      begin
        readln(x);
        if c[x] <> 0 then begin
        writeln(a[c[x]]);
        c[x] := b[c[x]];     end;
      end;
    end;
  close(input); close(output);
end.

nobody wants to help me?

100000>32768, b[] may overflow (word)