Solve the programming task below in a Python markdown code block.
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.

Examples

Input

2 3 2


Output

5


Input

13 14 1


Output

14


Input

14 5 9


Output

464


Input

17 18 3


Output

53