Two Chickens (...)

Time limit2sMemory limit512 MB

Summary

Given two account balances and the price of one chicken, print the leftover total if two chickens can be afforded, otherwise the current total.

Level: Easy1 of 10
Topics: Implementation, Math, Brute force
Solved: No attempts yet

Problem

Sadly, the prizes for the 2017 Sunrin spring school contest are paid out of Ukje's bank accounts. Whether or not they know how Ukje feels, the participants keep begging for no fewer than two chickens (...) as the first prize.

Ukje has two bank accounts. Given the balances of both accounts and the price of one chicken, find out whether Ukje can buy two chickens (...). He can combine the balances of both accounts to pay.

Input

The first line contains the balances $A$ and $B$ of the two accounts. ( $0 \le A, B \le 1\,000\,000\,000$ )

The second line contains the price $C$ of one chicken. ( $0 \le C \le 1\,000\,000\,001$ )

Output

If Ukje can buy two chickens (...), print the sum of the two account balances left after buying them. Otherwise, print the current sum of the two account balances.

Examples3

Example 1
Input
```
87 31
20000
```
Expected output
```
118
```
Example 2
Input
```
15000 6000
5000
```
Expected output
```
11000
```

Example 3

Input

1000000000 1000000000
1000000001

Expected output

2000000000