^{4}]. The first one who bets on a unique number wins. For example, if there are 7 people betting on 5 31 5 88 67 88 17, then the second one who bets on 31 wins.

Submit: 722 Solved: 445

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Being unique is so important to people on Mars that even their lottery is designed in a unique way. The rule of winning is simple: one bets on a number chosen from [1, 10^{4}]. The first one who bets on a unique number wins. For example, if there are 7 people betting on 5 31 5 88 67 88 17, then the second one who bets on 31 wins.

Each input file contains one test case. Each case contains a line which begins with a positive integer N (<=10^{5}) and then followed by N bets. The numbers are separated by a space.

For each test case, print the winning number in a line. If there is no winner, print "None" instead.

```
7 5 31 5 88 67 88 17
5 888 666 666 888 888
```

```
31
None
```