#include<bits/stdc++.h>
using namespace std;
int main(){
	int b[3]={},n,f=0;
	string a;
	cin>>n>>a;
	for(int i=0;i<n;i++) 
	{
		--a[i];
		if(a[i]=='1') f=1;
		b[a[i]-'0']+=(((n-1)&i)==i);
	}
	if(b[1]&1) cout<<"1";
	else if(!f&&(b[2]&1)) cout<<"2";
	else cout<<"0";
	return 0;
}

### Prompt

Your task is to create a cpp solution to the following 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

### Response

```cpp
#include<bits/stdc++.h>
using namespace std;
int main(){
	int b[3]={},n,f=0;
	string a;
	cin>>n>>a;
	for(int i=0;i<n;i++) 
	{
		--a[i];
		if(a[i]=='1') f=1;
		b[a[i]-'0']+=(((n-1)&i)==i);
	}
	if(b[1]&1) cout<<"1";
	else if(!f&&(b[2]&1)) cout<<"2";
	else cout<<"0";
	return 0;
}

```