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:
def main():
    n=int(input())
    A=list(map(lambda x: int(x)-1,list(input().strip())))
    ans=1
    if not 1 in A:
        ans*=2
        for i in range(n):
            A[i]>>=1
    parity=0
    for i in range(n):
        if (n-1)&i==i:
            parity^=A[i]&1
    ans*=parity
    print(ans)
    
if __name__=='__main__':
    main()