Mysterious numbers - 2

Description:

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.

Sample Input:

2 3 2

Sample Output:

5

Sample Input:

13 14 1

Sample Output:

14

Sample Input:

14 5 9

Sample Output:

464

Sample Input:

17 18 3

Sample Output:

53