Codeforces 556A 贪心

Andrewid the Android is a galaxy-famous detective. In his free time he likes to think about strings containing zeros and ones.

Once he thought about a string of length n consisting of zeroes and ones. Consider the following operation: we choose any two adjacent positions in the string, and if one them contains 0, and the other contains 1, then we are allowed to remove these two digits from the string, obtaining a string of length n - 2 as a result.

Now Andreid thinks about what is the minimum length of the string that can remain after applying the described operation several times (possibly, zero)? Help him to calculate this number.

Input

First line of the input contains a single integer n (1 ≤ n ≤ 2·105), the length of the string that Andreid has.

The second line contains the string of length n consisting only from zeros and ones.

Output

Output the minimum length of the string that may remain after applying the described operations several times.

Example

Input

4

1100

Output

0

Input

5

01010

Output

1

Input

8

11101111

Output

6

010 无论是删除01还是10最终得到的长度都是一样的。

而且最后得到的结果肯定是纯1或者纯0，智障题- -

#include <string>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <stack>
#include <cstdio>
using namespace std;
string s;
int main()
{
int n;
while(scanf("%d",&n)!=EOF)
{
cin>>s;
int a=0,b=0;
for(int i=0;i<s.length();i++)
{
if(s[i]=='0')
a++;
else b++;
}
printf("%d\n",a>b?a-b:b-a);
}
}