The number M = 124563987 is the smallest number which uses all the non-zero digits once each and which has the property that none of the pairs of its consecutive digits makes a prime number. For example, the 5th and 6th digits of M make the number 63 which is not prime. N is the largest number which uses all the non-zero digits once each and which has the property that none of the pairs of its consecutive digits makes a prime number. What are the 5th and 6th digits of N?
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6 and 3
5 and 4
5 and 2
4 and 8
3 and 5
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