Task: Question Answering
Input (English): Passage: Percy Caldwell is a teenage boy who lives in Pine Bluffs, California. He is in love with Madison, his high school's most popular cheerleader, but his best friend Leonard doesn't think he stands a chance. One day, after Percy rescues Madison from two local bullies, brothers named Cletis and Devlin, the brothers knock his bicycle off the road with their truck, and Percy ends up crashing in the woods, falling unconscious.
When Percy wakes up, he sees a seven-foot-tall Bigfoot standing over him. Percy is initially scared, but the creature seems friendly and interacts with him. Then, Percy rushes home where he tells his parents but they do not believe him.
The next day, Madison thanks Percy for saving her from the bullies; giving him a kiss and declaring him her boyfriend. After school, Percy goes to see the Sasquatch in the woods and they share a picnic. Cletis and Devlin, who are going bear hunting, hear the Sasquatch burp from a distance and mistake him for a Grizzly bear.Percy hears the hunters and tells the Sasquatch to flee. When the brothers find Percy they threaten him, and Bigfoot comes to Percy's rescue; throwing the brothers down a hill. After that, the brothers start planning to catch the creature to sell for big money.
The next morning Percy goes back into the woods for another picnic with Bigfoot. When he gets home, Madison arrives. While they are watching King Kong, Percy tells Madison about his encounters with the Sasquatch but she doesn't believe him and begins to have doubts about him. Meanwhile, Cletis and Devlin are building a cage for the Sasquatch in their barn.
The following day, Percy tells Madison and Leonard to follow him to go see the Sasquatch, but Madison then decides that their relationship is over and she leaves. Leonard, however, agrees to go with him. 
Question: What is the last name of the person who falls unconscious?
Output (English): Caldwell.