I need help with the following question.

ACM ICPC Kharagpur Regionals 2017 Question
I need help with the following question.

| Rev. | Lang. | By | When | Δ | Comment | |
|---|---|---|---|---|---|---|
| en3 |
|
back_slash | 2017-12-21 18:48:12 | 165 | ||
| en2 |
|
back_slash | 2017-12-20 16:53:58 | 142 | ||
| en1 |
|
back_slash | 2017-12-20 14:19:35 | 157 | Initial revision (published) |