Solve in Python:
[Image] 


-----Input-----

The input contains a single integer $a$ ($0 \le a \le 15$).


-----Output-----

Output a single integer.


-----Example-----
Input
3

Output
13
n = int(input())

a = [0] * 4

i = 0
for i in range(4):
    a[i] = n % 2
    n = n // 2


a[3] = a[3] ^ 1
a[2] = a[3] ^ a[2]
a[1] = (a[3] and a[2]) ^ a[1]
a[0] = (a[3] and a[2] and a[1]) ^ a[0]

sum_ = 0
for i in range(4):
    sum_ += a[i] * 2 ** i

print(sum_)