G. Mysterious numbers - 2
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output
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