function cars(A = [0, 1, 0, 1, 1]) {
  let s = 0;
  const countedA = A.reverse().map(x => {
    if (!x) {
      return 0
    }
    s++;
    return s
  }).reverse();

  let sum = 0;
  while(countedA.length) {
    const car = countedA.shift();
    if(car) {
      continue
    }
    const count = countedA.find(n => n > 0);
    sum = sum + count;
  }
  return sum
}