0 and 1

Description

Andrewid The Android is a galaxy-famous detective. In the He 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 of the adjacentpositions in the string, and if one them contains 0, and T He other contains 1, then we is allowed to remove these and digits from the string, obtaining a string of length N -2 as a result.

Now Andreid thinks on what's the minimum length of the string that can remain after applying the described Operation s Everal Times (possibly, zero)? Help him to calculate this number.

Input

First line of the input contains a single integer n (1≤ n ≤2 10^{5), the length of the Strin G that Andreid have.}

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

Output

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

Sample Input

Input

4
1100

Output

0

Input

5
01010

Output

1

Input

8
11101111

Output

6

Hint

In the first sample test it's possible to change the string like the following:.

In the second sample test it's possible to change the string like the following:.

In the third sample test it's possible to change the string like the following:.

Test instructions

0 and 1 met to cancel each other out.

And let you find the minimum length of the sequence

With n 0 M 1;

Ans=str.length ()-(Max (n,m)-min (n,m));

1#include <iostream>2 using namespacestd;3 intMain () {4     intN;5      while(cin>>n&&N) {6Cin.Get();7         ints=0;8         ints1=0;9          for(intI=0; i<n;i++){Ten             if(CIN.)Get()=='0') s++; One         } ACin.Get(); -s1=n-s; -cout<<n-2* (S1&GT;S?S:S1) <<Endl; the     } - return 0; -}

View Code

0 and 1