of his friends.

is participating in a push-up contest withEach participant does a unique number of push-ups between and . However, was too busy organizing DMPG and unfortunately forgot how many push-ups he did!

As

is worried about whether or not , with his wonderfully toned figure and boyish charm, won the contest, help him figure out how many push ups he did, given the number of push ups done by the other participants.#### Input Specification

The first line of input with consist of integer, .

The next lines will consist of the number of push-ups that each of 's friends did.

#### Output Specification

The number of push-ups that

did.#### Sample Input

```
5
1
2
3
5
```

#### Sample Output

`4`

## Comments

wow that is a lot of push-ups, very nice