C. 668.

(5 points)

Deadline expired.

Statistics on problem C. 668. 187 students sent a solution. 5 points: 121 students. 4 points: 5 students. 3 points: 2 students. 2 points: 14 students. 1 point: 32 students. 0 point: 9 students. Unfair, not evaluated: 4 solutions.