Problems
Fibonacci strings generation
Fibonacci strings generation
Generate n-th Fibonacci string that is defined with the next recurrent formula:
f(0) = "a";
f(1) = "b";
f(n) = f(n - 1) + f(n - 2), where "+" operation means concatenation
For example, f(3) = f(2) + f(1) = (f(1) + f(0)) + f(1) = "b" + "a" + "b" = "bab".
Input data
One integer n~(0 \le n \le 20).
Output data
Print the n-th Fibonacci string.
Examples
Input example #1
3
Output example #1
bab
Input example #2
5
Output example #2
babbabab