task main()
{
ClearScreen();
string a;
byte n, nt, k;
a = "STOP";
n = 9;
nt = 0;
k = 100;
SetSensorType(IN_4, SENSOR_TYPE_HIGHSPEED);
SetHSState(HS_INITIALISE);
SetHSFlags(HS_UPDATE);
byte mlen;
string buffer;
SetHSInputBufferInPtr(0);
SetHSInputBufferOutPtr(0);
Wait(10);
  while(true)
  {
    mlen = 0;
    while (mlen == 0)
    mlen = HSInputBufferInPtr();
    Wait(2);
    mlen = HSInputBufferInPtr();
    GetHSInputBuffer(0, mlen, buffer);
    SetHSInputBufferInPtr(0);
    TextOut(0, LCD_LINE1, buffer);
    n = StrToNum(buffer);
      if (n <> nt)
      {
      nt = n;
      if (n < 10) // circle mode
      {
        switch(n)
        {
          case 9:
           Off(OUT_AB);
           // a = "STOP";
          break;
          case 1:
            OnRev(OUT_AB , k);
            // a = "N";
          break;
          case 2:
            Off(OUT_AB);
            // a = "NW";
          break;
          case 3:
            OnFwd(OUT_AB , k);
            // a = "W";
          break;
          case 4:
            Off(OUT_AB);
            // a = "SW";
          break;
          case 5:
            OnFwd(OUT_AB , k);
            // a = "S";
          break;
          case 6:
            OnFwd(OUT_AB , k);
            // a = "SO";
          break;
          case 7:
            OnRev(OUT_AB , k);
            // a = "O";
          break;
          case 8:
            OnRev(OUT_AB , k);
            // a = "NO";
          break;
        }
      }
      else  // parallel mode
      {
        switch(n)
        {
          case 19:
           Off(OUT_AB);
           // a = "STOP";
          break;
          case 11:
            OnRev(OUT_AB , k);
            // a = "N";
          break;
          case 12:
            Off(OUT_A);
            OnRev(OUT_B , k);
            // a = "NW";
          break;
          case 13:
            OnFwd(OUT_A , k);
            OnRev(OUT_B , k);
            // a = "W";
          break;
          case 14:
            Off(OUT_B);
            OnFwd(OUT_A , k);
            // a = "SW";
          break;
          case 15:
            OnFwd(OUT_AB , k);
            // a = "S";
          break;
          case 16:
            Off(OUT_A);
            OnFwd(OUT_B , k);
            // a = "SO";
          break;
          case 17:
            OnFwd(OUT_B , k);
            OnRev(OUT_A , k);
            // a = "O";
          break;
          case 18:
            Off(OUT_B);
            OnRev(OUT_A , k);
            // a = "NO";
          break;
        }
      }
      // ClearScreen();
      // TextOut(0, LCD_LINE1, a);
    }
  }
}