Problem:
Score : 700 points

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}.

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}.

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

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<bits/c++config.h>
#include <iostream>


using namespace std;
#include <utility>
#include<stdio.h>
#include <stdio.h>
#include <stdlib.h>
int main(){
  long long int N=0;
  long long int S = 0;
  int A[N][N];
  int F = 10;
  scanf("%d\n",&N);
  scanf("%lld",&S);
  for (int i=1;i<N;i++){
    A[N-i-1][0] = (S/F)%10;
    F *= 10;
  }
  A[N-1][0] = S%10;
  for(int i = 1;i<N;i++){
    for(int j = 0;j < N;j++){
      A[i][j] = abs(A[i-1][j]-A[i-1][j+1]);
    }
  }
  printf("%d",A[N][0]);
  
  
}