Problem:
Score : 100 points

Problem Statement

Takahashi is going to set a 3-character password.

How many possible passwords are there if each of its characters must be a digit between 1 and N (inclusive)?

Constraints

1 \leq N \leq 9

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the number of possible passwords.

Sample Input 1

2

Sample Output 1

8

There are eight possible passwords: 111, 112, 121, 122, 211, 212, 221, and 222.

Sample Input 2

1

Sample Output 2

1

There is only one possible password if you can only use one kind of character.

Solution in Ruby (2.3.3) (judge verdict: Runtime Error)

a = []
b = []
n = gets.chomp.to_i
b = gets.chomp.split(" ").map(&:to_i)

bl = n-1

for i in 0...bl do
  if i ==0
    a[i]=a[i+1]=b[i]
  end

  if b[i]<a[i]
    a[i]=a[i+1]=b[i]
  else
    a[i+1]=b[i]
  end
end

puts a.inject(:+)