Types: n: int, h: int, ci: str, ai: int, bi: int

Ranges: 1 ≤ n ≤ 500, 0 ≤ h ≤ 200, ci in {"xy", "xz", "yz"}, 1 ≤ ai, bi ≤ n

Addtl Info: Input terminates with n = 0 and h = 0