B'Petya loves lucky numbers. Everybody knows that lucky numbers are positive integers whose decimal representation contains only the lucky digits 4 and 7. For example, numbers 47, 744, 4 are lucky and 5, 17, 467 are not. One day Petya dreamt of a lexicographically k-th permutation of integers from 1 to n. Determine how many lucky numbers in the permutation are located on the positions whose indexes are also lucky numbers. The first line contains two integers n and k (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n, xe2 x80 x89k xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89109) -- the number of elements in the permutation and the lexicographical number of the permutation. If the k-th permutation of numbers from 1 to n does not exist, print the single number "-1" (without the quotes). Otherwise, print the answer to the problem: the number of such indexes i, that i and ai are both lucky numbers. A permutation is an ordered set of n elements, where each integer from 1 to n occurs exactly once. The element of permutation in position with index i is denoted as ai (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89i xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n). Permutation a is lexicographically smaller that permutation b if there is such a i (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89i xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n), that ai xe2 x80 x89< xe2 x80 x89bi, and for any j (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89j xe2 x80 x89< xe2 x80 x89i) aj xe2 x80 x89= xe2 x80 x89bj. Let 's make a list of all possible permutations of n elements and sort it in the order of lexicographical increasing. Then the lexicographically k-th permutation is the k-th element of this list of permutations. In the first sample the permutation looks like that: 1 2 3 4 6 7 5 The only suitable position is 4. In the second sample the permutation looks like that: 2 1 3 4 The only suitable position is 4.'...