import algorithm, future, hashes, macros, math, sequtils, sets, strutils, tables, unicode template readString: string = stdin.readLine template readStrings: seq[string] = stdin.readLine.split template readInt: int = stdin.readLine.parseInt template readInts: seq[int] = stdin.readLine.split.map(parseInt) template readFloat: float = stdin.readLine.parseFloat template readFloats: seq[float] = stdin.readLine.split.map(parseFloat) template times(n: int, body: untyped): untyped = (for _ in 0..<n: body) proc newSeq2[T](n1, n2: Natural): seq[seq[T]] = newSeqWith(n1, newSeq[T](n2)) proc newSeq3[T](n1, n2, n3: Natural): seq[seq[seq[T]]] = newSeqWith(n1, newSeqWith(n2, newSeq[T](n3))) macro unpack*(rhs: seq, cnt: static[int]): auto = let t = genSym(); result = quote do:(let `t` = `rhs`;()) for i in 0..<cnt: result[0][1].add(quote do:`t`[`i`]) # -------------------------------------------------- # var N = readString if N[0] != '1': echo -1 quit() if N == "1": echo -1 quit() for i in 1..<N.len: if N[i] != '3': echo -1 quit() echo N.len - 1