function equalStacks(h1, h2, h3) {
  let size1 = 0,
    size2 = 0,
    size3 = 0,
    maxSize = 0;
  while (true) {
    if (size1 === size2 && size2 === size3) maxSize = size1;
    if (!h1.length && !h2.length && !h3.length) {
      break;
    }
    
    if (size1 <= size2 && size1 <= size3 && h1.length) {
      size1 += h1.pop();
    } else if (size2 <= size1 && size2 <= size3 && h2.length) {
      size2 += h2.pop();
    } else if (size3 <= size1 && size3 <= size2 && h3.length) {
      size3 += h3.pop();
    }else break
  }

  return maxSize;
}