PROGRAMMING:Find a common elective course - heboost

Each student's favorite programming language is different, please program to find a programming language that everyone likes.
###Input format:
The first line of input is the number of records
After the first line is the record of each student's programming language. The names and programming languages are separated directly by English colons, and the programming languages are separated by spaces.
###Output format:
The output is a common favorite programming language (if the result is empty, output none).
###Input example:
Here is a set of inputs. For example:
```in
three
gcs:java js php
cxy:js python c++
sds:c++ c js
```
###Output example:
The corresponding output is given here. For example:
```out
js
```







answer：If there is no answer, please comment