Poor Computer

Time Limit : 8 sec, Memory Limit : 131072 KB

Problem F: Poor Computer

Brian Fulk is struggling with a really poor computer for a couple of days. Now he is trying to write a very simple program which receives a positive integer x and returns some of its multiples, say, a1x,...,aNx. However, even such a simple task is not easy on this computer since it has only three arithmetic operations: addition, subtraction and left shift.

Let us describe the situation in more details. Initially the computer stores only a given positive integer x. The program Brian is writing will produce a1x,..., aNx, where a1,...,aN are given multipliers, using only the following operations:

  • addition of two values,
  • subtraction of two values, and
  • bitwise left shift (left shift by n bits is equivalent to multiplication by 2n).

The program should not generate any value greater than 42x; under this constraint he can assume that no overflow occurs. Also, since this computer cannot represent negative values, there should not be subtraction of a greater value from a smaller value.

Some of you may wonder where the number 42 comes from. There is a deep reason related to the answer to life, the universe and everything, but we don't have enough space and time to describe it.

Your task is to write a program that finds the shortest sequence of operations to produce the multiples a1x,...,aNx and reports the length of the sequence. These numbers may be produced in any order.

Here we give an example sequence for the first sample input, in a C++/Java-like language:

a = x << 1;  // 2x
b = x + a;   // 3x
c = a + b;   // 5x
d = c << 2;  // 20x
e = d - b;   // 18x


The first line specifies N, the number of multipliers. The second line contains N integers a1,..., aN, each of which represents a multiplier of x.

You can assume that N ≤ 41 and 2 ≤ ai ≤ 42 (1 ≤ iN). Furthermore, a1,...,aN are all distinct.


Output in a line the minimum number of operations you need to produce the values a1x,...,aNx.

Sample Input and Output

Input #1

3 5 18

Output #1


Input #2


Output #2


Input #3

12 19 41 42

Output #3


Source: ACM-ICPC Japan Alumni Group Winter Camp , Day 3, Tokyo, Japan, 2009-02-23