B'Fox Ciel is participating in a party in Prime Kingdom. There are n foxes there (include Fox Ciel). The i-th fox is ai years old. They will have dinner around some round tables. You want to distribute foxes such that: If k foxes f1, f2, ..., fk are sitting around table in clockwise order, then for 1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89i xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89k xe2 x80 x89- xe2 x80 x891: fi and fi xe2 x80 x89+ xe2 x80 x891 are adjacent, and f1 and fk are also adjacent. If it is possible to distribute the foxes in the desired manner, find out a way to do that. The first line contains single integer n (3 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89200): the number of foxes in this party. The second line contains n integers ai (2 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89ai xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89104). If it is impossible to do this, output "Impossible". Otherwise, in the first line output an integer m (): the number of tables. Then output m lines, each line should start with an integer k -= xe2 x80 x93 the number of foxes around that table, and then k numbers -- indices of fox sitting around that table in clockwise order. If there are several possible arrangements, output any of them. In example 1, they can sit around one table, their ages are: 3-8-9-4, adjacent sums are: 11, 17, 13 and 7, all those integers are primes. In example 2, it is not possible: the sum of 2+2 = 4 is not a prime number.'...