let startHeight = 384120
let finishHeight = startHeight + 3000
let startPrice = 100000
#extracting the sender’s address from the transaction
let this = extract(tx.sender)
let token = base58'8jfD2JBLe23XtCCSQoTx5eAW5QCU6Mbxi3r78aNQLcNf'
match tx {
  case d : DataTransaction =>
      #checking if the price is defined in the state
      let currentPrice = if isDefined(getInteger(this, "price"))
      #extracting the price from the state
      then extract(getInteger(this, "price"))
      else startPrice

      #extracting the price from the transaction
      let newPrice = extract(getInteger(d.data, "price"))
      let priceIsBigger = newPrice > currentPrice
      let fee = 700000
      let hasMoney = wavesBalance(tx.sender) + fee >= newPrice

      #making sure there are two fields in the current transaction and the sender is the same as the same as stated in the transaction
      let correctFields = size(d.data) == 2 &&
      d.sender == addressFromString(extract(getString(d.data,"sender")))
      startHeight <= height && height <= finishHeight && priceIsBigger && hasMoney && correctFields
  case e : ExchangeTransaction =>
      let senderIsWinner = e.sender == addressFromString(extract(getString(this, "sender"))) #making sure that the item is exchanged by the actual winner
      let correctAssetPair = e.sellOrder.assetPair.amountAsset == token && ! isDefined(e.sellOrder.assetPair.priceAsset)
      let correctAmount = e.amount == 1
      let correctPrice = e.price == extract(getInteger(this, "price"))
      height > finishHeight && senderIsWinner && correctAssetPair && correctAmount && correctPrice
  case _ => false
}