TASK DEFINITION: In this task your given two statements. You must judge whether the second sentence is the cause or effect of the first one. Label the instances as "cause" or "effect" based on your judgment. The sentences are separated by a newline character.
PROBLEM: The elevator doors opened.
The elevator arrived at the designated floor.

SOLUTION: cause

PROBLEM: The boy's back ached.
His backpack was heavy.

SOLUTION: cause

PROBLEM: The building was evacuated.
The fire alarm went off.

SOLUTION:
cause

