문제<\/h2>
In ICPC, teamwork is everything. That's why everyone on your team has a well-defined role: Sol the Solver can solve any problem in the problem set, Codie the Coder can implement any solution that Sol comes up with, and you... are the glue that holds everything together. Sol and Codie are very picky about the order of problems they would solve\/code, and your job is to satisfy their preferences.<\/p>
There will be $n<\/mi><\/mrow>n<\/math><\/span><\/span> n<\/span><\/span><\/span><\/span> problems in the upcoming contest, and you know the general topic of each problem: greedy, geometry, graphs, etc. For simplicity, we will represent each topic with an integer from 1<\/mn><\/mrow>1<\/math><\/span><\/span> 1<\/span><\/span><\/span><\/span> to n<\/mi><\/mrow>n<\/math><\/span><\/span> n<\/span><\/span><\/span><\/span>. These integers don't have to be distinct, that is, multiple problems in the contest can have the same topic.<\/p> Sol wants to solve problems in a specific order of topics: first, the problem with the topic a<\/mi>1<\/mn><\/msub><\/mrow>a_1<\/math><\/span><\/span> a<\/span> <\/span> 1<\/span><\/span><\/span><\/span> <\/span><\/span> <\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>, after that, the problem with the topic$

First Solved, Last Coded