Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Driver | Constructor | Laps | Time/Retired | Grid |
| --- | --- | --- | --- | --- |
| Ralf Schumacher | Williams - BMW | 69.0 | 1:34:31.522 | 2.0 |
| Michael Schumacher | Ferrari | 69.0 | +20.235 | 1.0 |
| Mika Häkkinen | McLaren - Mercedes | 69.0 | +40.672 | 8.0 |
| Kimi Räikkönen | Sauber - Petronas | 69.0 | +1:08.116 | 7.0 |
| Jean Alesi | Prost - Acer | 69.0 | +1:10.435 | 16.0 |
| Pedro de la Rosa | Jaguar - Cosworth | 68.0 | +1 Lap | 14.0 |
| Ricardo Zonta | Jordan - Honda | 68.0 | +1 Lap | 12.0 |
| Luciano Burti | Prost - Acer | 68.0 | +1 Lap | 19.0 |
| Tarso Marques | Minardi - European | 66.0 | +3 Laps | 21.0 |
| Jos Verstappen | Arrows - Asiatech | 65.0 | Brakes | 13.0 |
| Jarno Trulli | Jordan - Honda | 63.0 | Brakes | 4.0 |
| David Coulthard | McLaren - Mercedes | 54.0 | Engine | 3.0 |
| Olivier Panis | BAR - Honda | 38.0 | Brakes | 6.0 |
| Jacques Villeneuve | BAR - Honda | 34.0 | Driveshaft | 9.0 |
| Enrique Bernoldi | Arrows - Asiatech | 24.0 | Engine | 17.0 |
| Juan Pablo Montoya | Williams - BMW | 19.0 | Accident | 10.0 |
| Rubens Barrichello | Ferrari | 19.0 | Spun off | 5.0 |
| Jenson Button | Benetton - Renault | 17.0 | Oil Leak | 20.0 |
| Fernando Alonso | Minardi - European | 7.0 | Transmission | 22.0 |
| Nick Heidfeld | Sauber - Petronas | 1.0 | Collision | 11.0 |
| Eddie Irvine | Jaguar - Cosworth | 1.0 | Collision | 15.0 |
| Giancarlo Fisichella | Benetton - Renault | 0.0 | Collision | 18.0 |
Question:
Which constructor had a Time/Retired of collision, where the grid number was less than 18 and Nick Heidfeld was the driver?
Answer:
Sauber - Petronas