 Complete the following phrase:  Williams retained defending world champion Keke Rosberg, but their number two seat, which had been occupied on a temporary basis by both Mario Andretti and Derek Daly in after the departure of Carlos Reutemann, was filled for 1983 by Ligiers Jacques Laffite. During the season Frank Williams signed an exclusive deal to use the turbocharged Honda V6 engines in his cars to replace the Cosworth DFV. Honda engines first appeared in the back of a Williams at the season-ending 