P6402 [COCI 2014/2015 #2] UTRKA

Many local and international recreational runners are eager to take part in this year’s Zagreb Marathon! This is a traditional race with a length of 42125 meters. A strange statistic is that this year, every competitor except one managed to finish the race. Please help the organizers determine the identity of the competitor who **did not finish the race**, based on the list of registered competitors and the ranking list.

The first line contains an integer $n$, the number of competitors. Each of the next $n$ lines contains the name of a registered competitor. The other $n - 1$ lines contain the names of the competitors who finished the race, listed in the order in which they finished. Competitor names consist of English letters. Competitor names are **not necessarily unique**.

The first and only line must contain the name of the competitor who did not finish the race.

#### Constraints - For $50\%$ of the testdata, $1 \le n \le 10^3$. - For $100\%$ of the testdata, $1 \le n \le 10^5$. Let $|s|$ be the length of a competitor’s name. Then for all valid names, $1 \le |s| \le 20$, and names consist only of **lowercase letters**. #### Notes **Translated from [COCI2014-2015](https://hsin.hr/coci/archive/2014_2015/) [CONTEST #2](https://hsin.hr/coci/archive/2014_2015/contest2_tasks.pdf) _T2 UTRKA_.** Translated by ChatGPT 5