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.

Input

The first line contains two integers $*n*$ and $*k*$ $(1 ≤ *n*, *k* ≤ 10^{9})$ — the number of elements in the permutation and the lexicographical number of the permutation.

Output

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 $*a*_{*i*}$ are both lucky numbers.

Note

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 $*a*_{*i*}$ ($1 ≤ *i* ≤ *n*$). Permutation $*a*$ is lexicographically smaller that permutation $*b*$ if there is such a $*i*$ ($1 ≤ *i* ≤ *n*$), that $*a*_{*i*} < *b*_{*i*}$, and for any $*j*$ ($1 ≤ *j* < *i*$) $*a*_{*j*} = *b*_{*j*}$. 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.