Problem Statement

Given is a sequence of $N digits a_1a_2\ldots a_N$, where each element is 1, 2, or 3.
Let x_{i,j} defined as follows:

• x_{1,j} :$= a_j \quad (1 \leq j \leq N)$
• x_{i,j} :$= | x_{i-1,j} - x_{i-1,j+1} | \quad (2 \leq i \leq N$ and $1 \leq j \leq N+1-i)$

Find x_{N,1}.

Input

Input is given from Standard Input in the following format:
N
$a_1a_2\ldotsa_N$

Output

Print x_{N,1}.

Constraints

• $2 \leq N \leq 10^6$
• $a_i = 1,2,3 (1 \leq i \leq N)$

Sample Input 1

4
1231

Sample Output 1

1

x_{1,1},x_{1,2},x_{1,3},x_{1,4} are respectively 1,2,3,1.
x_{2,1},x_{2,2},x_{2,3} are respectively |1-2| = 1,|2-3| = 1,|3-1| = 2.
x_{3,1},x_{3,2} are respectively |1-1| = 0,|1-2| = 1.
Finally, x_{4,1} = |0-1| = 1, so the answer is 1.

Sample Input 2

10
2311312312

Sample Output 2

0

见题面 Input 部分

见题面 Output 部分