Problem: 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}.

Constraints

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

Input

Input is given from Standard Input in the following format:


N
a_1a_2\ldotsa_N


Output

Print x_{N,1}.

Examples

Input

4
1231


Output

1


Input

10
2311312312


Output

0

Solution (in PYTHON3):

Solution:
import sys
n=int(input())
a=list(input())
A=[]
for i in range(n):
  a[i]=int(a[i])-1
  A.append(a[i]%2)

xorct=0
for i in range(n):
  if n-1==(i|n-1-i):
    xorct^=A[i]
if xorct==1:
  print(1)
  sys.exit()

if 1 in a:
  print(0)
  sys.exit()

for i in range(n):
  a[i]=a[i]//2
xorct=0
for i in range(n):
  if n-1==(i|n-1-i):
    xorct^=a[i]
if xorct==1:
  print(2)
  sys.exit()

print(0)