[Problem 4 | 1997 ACM North-Central Regionals problem set | Ed's Programming Contest Problem Archive | my home page]

The short story titled *Coconuts*, by Ben Ames Williams,
appeared in the *Saturday Evening Post* on October 9, 1926.
The story tells about five men and a monkey who were shipwrecked on an
island. They spent the first night gathering coconuts. During the
night, one man woke up and decided to take his share of the coconuts.
He divided them into five piles. One coconut was left over so he gave
it to the monkey, then hid his share and went back to sheep.

Soon a second man woke up and did the same thing. After dividing the coconuts into five piles, one coconut was left over which he gave to the monkey. He then hid his share and went back to bed. The third, fourth, and fifth man followed exactly the same procedure. The next morning, after they all woke up, they divided the remaining coconuts into five equal shares. This time no coconuts were left over.

An obvious question is "how many coconuts did they originally gather?" There are an infinite number of answers, but the lowest of these is 3,121. But that's not our problem here.

Suppose we turn the problem around. If we know the number of coconuts that were gathered, what is the maximum number of persons (and one monkey) that could have been shipwrecked if the same procedure could occur?

## Sample Input25 30 3121 -1 |
## Expected Input25 coconuts, 3 persons and 1 monkey 30 coconuts, no solution 3121 coconuts, 5 persons and 1 monkey |

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Last updated November 14, 1997