The Salt-Caravan of Dunmarrow Waste

The Salt-Caravan of Dunmarrow Waste leaves Bitwick at first light and crosses the dunes for weeks. Its master, Orsa Kell, pays escorts to keep the manifest. Every load lashed to a pack-beast gets a tag naming the day of the crossing it was loaded, how many sacks it holds and what is in them. The tax-posts along the Waste reject any tag not written in the exact form below.

Write caravanTag(goods, day, sacks), where:

• goods is a string naming the contents. Copy it into the tag exactly as given.
• day is a non-negative integer.
• sacks is a non-negative integer.

Return a string of the form:

Day DD: N sacks of GOODS

The parts are filled in as follows:

• DD is day padded with leading zeros to at least two digits. Day 7 becomes 07 and day 0 becomes 00. A day with three or more digits is written unchanged.
• N is sacks written plainly, with no padding.
• The word after N is sack when sacks is exactly 1, and sacks otherwise, including 0.
• GOODS is goods, unchanged.

The tag contains single spaces exactly where the form shows them. There is no trailing space or punctuation.