The zoo keeper of a major zoo wants to redo the zoo in such a way that the animals live together in their natural habitat. Unfortunately, it is not possible to put all the animals together in one location because some are predators of others. The dots in the chart below show which are predators or preys of others. What is the minimum number of locations the zoo keeper needs?
a
b
c
d
e
f
g
h
i
j
a
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b
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c
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d
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e
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f
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g
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h
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i
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j
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