#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0; i<(n); i++)
int n, a, ac, c, o;
char s[1000005];
int main(){
	scanf("%d\n%s", &n, s);
	rep(i,n){
		if(s[i] == '2') o = 2;
		if(i) c += __builtin_ctz(n-i) - __builtin_ctz(i);
		if(!c) ac ^= (s[i] - '1');
	}
	printf("%d\n", ac & ~o);
}
### Prompt

Please create a solution in cpp 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;
#define rep(i,n) for(int i=0; i<(n); i++)
int n, a, ac, c, o;
char s[1000005];
int main(){
	scanf("%d\n%s", &n, s);
	rep(i,n){
		if(s[i] == '2') o = 2;
		if(i) c += __builtin_ctz(n-i) - __builtin_ctz(i);
		if(!c) ac ^= (s[i] - '1');
	}
	printf("%d\n", ac & ~o);
}
```