CF346B Lucky Common Subsequence

In mathematics, a subsequence is a sequence that can be derived from another sequence by deleting some elements without changing the order of the remaining elements. For example, the sequence BDF is a subsequence of ABCDEF. A substring of a string is a continuous subsequence of the string. For example, BCD is a substring of ABCDEF. You are given two strings $ s_{1} $ , $ s_{2} $ and another string called $ virus $ . Your task is to find the longest common subsequence of $ s_{1} $ and $ s_{2} $ , such that it doesn't contain $ virus $ as a substring.

The input contains three strings in three separate lines: $ s_{1} $ , $ s_{2} $ and $ virus $ ( $ 1

Output the longest common subsequence of $ s_{1} $ and $ s_{2} $ without $ virus $ as a substring. If there are multiple answers, any of them will be accepted. If there is no valid common subsequence, output 0.