Problem Statement

Takahashi has A untasty cookies containing antidotes, B tasty cookies containing antidotes and C tasty cookies containing poison.
Eating a cookie containing poison results in a stomachache, and eating a cookie containing poison while having a stomachache results in a death.
As he wants to live, he cannot eat one in such a situation.
Eating a cookie containing antidotes while having a stomachache cures it, and there is no other way to cure stomachaches.
Find the maximum number of tasty cookies that Takahashi can eat.

Input

Input is given from Standard Input in the following format:
A B C

Output

Print the maximum number of tasty cookies that Takahashi can eat.

Constraints

• $0 \leq A,B,C \leq 10^9$
• A,B and C are integers.

Sample Input 1

3 1 4

Sample Output 1

5

We can eat all tasty cookies, in the following order:

• A tasty cookie containing poison
• An untasty cookie containing antidotes
• A tasty cookie containing poison
• A tasty cookie containing antidotes
• A tasty cookie containing poison
• An untasty cookie containing antidotes
• A tasty cookie containing poison

Sample Input 2

5 2 9

Sample Output 2

10

Sample Input 3

8 8 1

Sample Output 3

9

见题面 Input 部分

见题面 Output 部分