The PDF version of this problem can be downloaded here. The whole problemset as one file can be downloaded here.
2 5 3 1 2 3 2 3 4 1 3 5 7 7 1 2 1 3 4 2 4 3 2 3 1 4 5 6 7
YN
Migrated from old NTUJ.
2011 ICPC Phuket