function part2([ruleInput, myTicket, ticketInput]) {
const rules = parseRules(ruleInput);
const vTickets = validTickets(rules, ticketInput);
const fieldPositions = AOC.invertMap(
AOC.eliminate(rulesAtPositions(rules, vTickets))
);
return AOC.product(depVals(myTicket, departurePositions(fieldPositions)));
}