codeforces#P171G. Mysterious numbers - 2

Mysterious numbers - 2

Description

The only line of input contains three integers a1, a2, a3 (1 ≤ a1, a2, a3 ≤ 20), separated by spaces.

Output a single integer.

Input

The only line of input contains three integers a1, a2, a3 (1 ≤ a1, a2, a3 ≤ 20), separated by spaces.

Output

Output a single integer.

Samples

2 3 2

5

13 14 1

14

14 5 9

464

17 18 3

53