Print the KKK-th nnn-bit string in the reflective Gray code order (1-indexed KKK).
Integers nnn and KKK.
The KKK-th Gray code string of length nnn.
1≤n≤621 \le n \le 621≤n≤62, 1≤K≤2n1 \le K \le 2^n1≤K≤2n.