I also wa at #1,in my prog I need to know the space exact position.At first I don't know why wa at all!!!The test must be changed!!!!

  readln(n);
  fillchar(a,sizeof(a),0);
  fillchar(b,sizeof(b),0);
  while true do
  begin
    read(ch); while ch=' ' do read(ch);
    if ch='B' then
    begin
      readln;
      break;
    end;
    x:=0;
    while ch<>' ' do
    begin
      x:=x*10+ord(ch)-ord('0');
      read(ch);
    end;
    readln(y);
    insert(a[x],y); insert(b[y],x);
  end;

But you don't need to read character by character. You read a string, then delete all the spaces at its end, and you'll get AC.