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“Once upon a time, a princess was walking through a forest and stumbled
across a pond. Out of the pond rose a witch, who cackled, "Stop! I have turned
a handsome prince into a frog and cast him into my pond to live with 99
other frogs. Each frog has a different number on his back. The prince
has the largest number on his back, and this is your only way of spotting him.
You must find him and kiss him if you want to leave my enchanted forest.
The frogs will jump from the pond one by one. When each frog appears,
you must decide whether to kiss him or throw him back in, never to be seen
again. If you kiss a real frog, or don't kiss any of the 100 frogs, you
will never leave the forest, and the prince will remain in the pond."
And with a suitably evil laugh, the witch sank back into her murky pond.
Fortunately, the princess was very good at maths, and knew the best strategy
for deciding which frog to kiss.
” source...