Last Stone Weight

We have a collection of 'N' stones, each stone has a positive integer weight.

On each turn, we choose the two heaviest stones and smash them together. Suppose the stones have weights 'x' and 'y' with 'x' <= 'y'. The result of this smash will be:

1. If 'x' == 'y', both stones are totally destroyed;

2. If 'x' != 'y', the stone of weight 'x' is totally destroyed, and the stone of weight 'y' has a new weight equal to 'y - x'.

In the end, there is at most 1 stone left. Return the weight of this stone or 0 if there are no stones left.

Input format:

The first line of input contains the integer 'N', representing the total number of stones.

The second line of input contains 'N' single space-separated integers, representing the weights of the stones.

Output Format:

The only output line prints the weight of the last stone, if it exists, 0 otherwise.

Note:

You do not need to print anything; it has already been taken care of. Just implement the given functions.

Constraints :

1 <= N <= 10^5
1 <= W <= 10^6

Time Limit: 1 sec

Sample Input 1:

1
10

Sample Output 1:

10

Explanation For Sample Input 1:

There is Only one stone so the weight of the last stone is 10

Sample Input 2:

3
1 9 5

Sample Output 2:

3