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.

Constraints

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

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.