There are N integers, A_1, A_2, ..., A_N, arranged in a row in this order.

You can perform the following operation on this integer sequence any number of times:

Operation: Choose an integer i satisfying 1 \leq i \leq N-1. Multiply both A_i and A_{i+1} by -1.

Let B_1, B_2, ..., B_N be the integer sequence after your operations.

Find the maximum possible value of B_1 + B_2 + ... + B_N.

Constraints

* All values in input are integers.
* 2 \leq N \leq 10^5
* -10^9 \leq A_i \leq 10^9

Input

Input is given from Standard Input in the following format:


N
A_1 A_2 ... A_N


Output

Print the maximum possible value of B_1 + B_2 + ... + B_N.

Examples

Input

3
-10 5 -4


Output

19


Input

5
10 -4 -8 -11 3


Output

30


Input

11
-1000000000 1000000000 -1000000000 1000000000 -1000000000 0 1000000000 -1000000000 1000000000 -1000000000 1000000000


Output

10000000000
# coding:utf-8                                                                                         

import math
                                                                                                       
def main(n,a):                                                                                         
    n = int(n)                                                                                         
    a = a.split()
    cnt = 0
    minus = 0                                                                                          
    b = []                                                                                             
    for i in a:                                                                                        
        a[cnt] = int(i)                                                                                
        b.append(abs(int(i)))                                                                          
        if a[cnt] < 0:
            minus += 1                                                                                 
        cnt += 1 
    if minus % 2 != 0: 
        mini = min(b)                                                                                  
    else:       
        mini = 0 
    total = 0   
    for i in b: 
        total += abs(i)
    total -= 2 * abs(mini)                                                                             
    print total     
    return total
                                                                                                       
if __name__ == "__main__":                                                                             
    n = raw_input()
    a = raw_input()                                                                                    
    main(n,a)