how many drivers did not finish 56 laps?
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col : pos | no | driver | constructor | laps | time/retired | grid | points row 1 : 1 | 15 | sebastian vettel | red bull-renault | 56 | 1:57:43.485 | 1 | 10 row 2 : 2 | 14 | mark webber | red bull-renault | 56 | +10.970 | 3 | 8 row 3 : 3 | 22 | jenson button | brawn-mercedes | 56 | +44.975 | 5 | 6 row 4 : 4 | 23 | rubens barrichello | brawn-mercedes | 56 | +1:03.704 | 4 | 5 row 5 : 5 | 2‡ | heikki kovalainen | mclaren-mercedes | 56 | +1:05.102 | 12 | 4 row 6 : 6 | 1‡ | lewis hamilton | mclaren-mercedes | 56 | +1:11.866 | 9 | 3 row 7 : 7 | 10 | timo glock | toyota | 56 | +1:14.476 | 19 | 2 row 8 : 8 | 12 | sébastien buemi | toro rosso-ferrari | 56 | +1:16.439 | 10 | 1 row 9 : 9 | 7 | fernando alonso | renault | 56 | +1:24.309 | 2 |  row 10 : 10 | 4 | kimi räikkönen | ferrari | 56 | +1:31.750 | 8 |  row 11 : 11 | 11 | sébastien bourdais | toro rosso-ferrari | 56 | +1:34.156 | 15 |  row 12 : 12 | 6‡ | nick heidfeld | bmw sauber | 56 | +1:35.834 | 11 |  row 13 : 13 | 5 | robert kubica | bmw sauber | 56 | +1:46.853 | 17 |  row 14 : 14 | 21 | giancarlo fisichella | force india-mercedes | 55 | +1 lap | 20 |  row 15 : 15 | 16 | nico rosberg | williams-toyota | 55 | +1 lap | 7 |  row 16 : 16 | 8 | nelson piquet, jr. | renault | 54 | +2 laps | 16 |  row 17 : 17 | 20 | adrian sutil | force india-mercedes | 50 | accident | 18 |  row 18 : ret | 17 | kazuki nakajima | williams-toyota | 43 | transmission | 14 |  row 19 : ret | 3 | felipe massa | ferrari | 20 | electrical | 13 |  row 20 : ret | 9 | jarno trulli | toyota | 18 | collision damage | 6 |
how many drivers did not finish 56 laps?
Pos No Driver Constructor Laps Time/Retired Grid Points
1 15 Sebastian Vettel Red Bull-Renault 56 1:57:43.485 1 10
2 14 Mark Webber Red Bull-Renault 56 +10.970 3 8
3 22 Jenson Button Brawn-Mercedes 56 +44.975 5 6
4 23 Rubens Barrichello Brawn-Mercedes 56 +1:03.704 4 5
5 2‡ Heikki Kovalainen McLaren-Mercedes 56 +1:05.102 12 4
6 1‡ Lewis Hamilton McLaren-Mercedes 56 +1:11.866 9 3
7 10 Timo Glock Toyota 56 +1:14.476 19 2
8 12 Sébastien Buemi Toro Rosso-Ferrari 56 +1:16.439 10 1
9 7 Fernando Alonso Renault 56 +1:24.309 2
10 4 Kimi Räikkönen Ferrari 56 +1:31.750 8
11 11 Sébastien Bourdais Toro Rosso-Ferrari 56 +1:34.156 15
12 6‡ Nick Heidfeld BMW Sauber 56 +1:35.834 11
13 5 Robert Kubica BMW Sauber 56 +1:46.853 17
14 21 Giancarlo Fisichella Force India-Mercedes 55 +1 Lap 20
15 16 Nico Rosberg Williams-Toyota 55 +1 Lap 7
16 8 Nelson Piquet, Jr. Renault 54 +2 Laps 16
17 20 Adrian Sutil Force India-Mercedes 50 Accident 18
Ret 17 Kazuki Nakajima Williams-Toyota 43 Transmission 14
Ret 3 Felipe Massa Ferrari 20 Electrical 13
Ret 9 Jarno Trulli Toyota 18 Collision damage 6
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