A bracketed sequence is called correct (regular) if by inserting "+" and "1" you can get a well-formed mathematical expression from it. For example, sequences "(())()", "()" and "(()(()))" are correct, while ")(", "(()" and "(()))(" are not.

The teacher gave Dmitry's class a very strange task — she asked every student to come up with a sequence of arbitrary length, consisting only of opening and closing brackets. After that all the students took turns naming the sequences they had invented. When Dima's turn came, he suddenly realized that all his classmates got the correct bracketed sequence, and whether he got the correct bracketed sequence, he did not know.

Dima suspects now that he simply missed the word "correct" in the task statement, so now he wants to save the situation by modifying his sequence slightly. More precisely, he can the arbitrary number of times (possibly zero) perform the reorder operation.

The reorder operation consists of choosing an arbitrary consecutive subsegment (substring) of the sequence and then reordering all the characters in it in an arbitrary way. Such operation takes l nanoseconds, where l is the length of the subsegment being reordered. It's easy to see that reorder operation doesn't change the number of opening and closing brackets. For example for "))((" he can choose the substring ")(" and do reorder ")()(" (this operation will take 2 nanoseconds).

Since Dima will soon have to answer, he wants to make his sequence correct as fast as possible. Help him to do this, or determine that it's impossible.

Input

The first line contains a single integer n (1 ≤ n ≤ 10^6) — the length of Dima's sequence.

The second line contains string of length n, consisting of characters "(" and ")" only.

Output

Print a single integer — the minimum number of nanoseconds to make the sequence correct or "-1" if it is impossible to do so.

Examples

Input


8
))((())(


Output


6


Input


3
(()


Output


-1

Note

In the first example we can firstly reorder the segment from first to the fourth character, replacing it with "()()", the whole sequence will be "()()())(". And then reorder the segment from the seventh to eighth character, replacing it with "()". In the end the sequence will be "()()()()", while the total time spent is 4 + 2 = 6 nanoseconds.
import java.io.*;
import java.lang.Math;
import java.util.*;

public class Main  {

    public BufferedReader in;
    public PrintStream out;

    public boolean log_enabled = false;
    
    public boolean multiply_tests = false;

    public static boolean do_gen_test = false;
    
    public void gen_test() {
            
        
    }
    
    private class TestCase {

        public Object solve() {
            
            
            int n = readInt();
            String s = readLn();
            
            int i, r = 0, c = 0, m = -1;
            
            for (i=0; i<n; i++)
            {
                if (s.charAt(i) == '(')
                {
                    c ++;
                }
                else
                {
                    c --;
                }
                
                if (c == 0)
                {
                    if (m>-1)
                    {
                        r += i-m+1;
                    }
                    m = -1;
                }
                
                if ((c<0) && (m==-1))
                {
                    m = i;
                }
            }
            
            if (c != 0)
            {
                return -1;
            }
            
            return r;
            
            //return strf("%f", 0);
            
            //out.printf("Case #%d: \n", caseNumber);
            //return null;
        }
        
        public int caseNumber;
        
        TestCase(int number) {
            caseNumber = number;
        }
        
        public void run(){
            Object r = this.solve();
            
            if ((r != null))
            {
                //outputCaseNumber(r);
                out.println(r);
            }
        }
        
        public String impossible(){
            return "IMPOSSIBLE";
        }
        
        public String strf(String format, Object... args)
        {
            return String.format(format, args);
        }
        
//        public void outputCaseNumber(Object r){
//            //out.printf("Case #%d:", caseNumber);
//            if (r != null)
//            {
//              //  out.print(" ");
//                out.print(r);
//            }
//            out.print("\n");
//        }
    }

    public void run() {
        //while (true)
        {
            int t = multiply_tests ?  readInt() : 1;
            for (int i = 0; i < t; i++) {
                TestCase T = new TestCase(i + 1);
                T.run();
            }
        }
    }
    

    
    public Main(BufferedReader _in, PrintStream _out){
        in = _in;
        out = _out;
    }
    

    public static void main(String args[]) {
        Locale.setDefault(Locale.US);
        Main S;
        try {
            S = new Main(
                        new BufferedReader(new InputStreamReader(System.in)),
                        System.out
                );
        } catch (Exception e) {
            return;
        }
        
        S.run();
        
    }

    private StringTokenizer tokenizer = null;

    public int readInt() {
        return Integer.parseInt(readToken());
    }

    public long readLong() {
        return Long.parseLong(readToken());
    }

    public double readDouble() {
        return Double.parseDouble(readToken());
    }

    public String readLn() {
        try {
            String s;
            while ((s = in.readLine()).length() == 0);
            return s;
        } catch (Exception e) {
            return "";
        }
    }

    public String readToken() {
        try {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                tokenizer = new StringTokenizer(in.readLine());
            }
            return tokenizer.nextToken();
        } catch (Exception e) {
            return "";
        }
    }

    public int[] readIntArray(int n) {
        int[] x = new int[n];
        readIntArray(x, n);
        return x;
    }
    
    public int[] readIntArrayBuf(int n) {
        int[] x = new int[n];
        readIntArrayBuf(x, n);
        return x;
    }

    public void readIntArray(int[] x, int n) {
        for (int i = 0; i < n; i++) {
            x[i] = readInt();
        }
    }
    
    public long[] readLongArray(int n) {
        long[] x = new long[n];
        readLongArray(x, n);
        return x;
    }
    
    public long[] readLongArrayBuf(int n) {
        long[] x = new long[n];
        readLongArrayBuf(x, n);
        return x;
    }

    public void readLongArray(long[] x, int n) {
        for (int i = 0; i < n; i++) {
            x[i] = readLong();
        }
    }

    public void logWrite(String format, Object... args) {
        if (!log_enabled) {
            return;
        }

        out.printf(format, args);
    }
    
    public void readLongArrayBuf(long[] x, int n) {
        
        char[]buf = new char[1000000];
        long r = -1;
        int k= 0, l = 0;
        long d;
        
        while (true)
        {
            try{
                l = in.read(buf, 0, 1000000);
            }
            catch(Exception E){};
            
            for (int i=0; i<l; i++)
            {
                if (('0'<=buf[i])&&(buf[i]<='9'))
                {
                    if (r == -1)
                    {
                        r = 0;
                    }
                    d = buf[i] - '0';
                    r = 10 * r + d;
                }
                else
                {
                    if (r != -1)
                    {
                        x[k++] = r;
                    }
                    
                    r = -1;
                }
            }
            
            if (l<1000000)
                return;
        }
    }
    
    public void readIntArrayBuf(int[] x, int n) {
        
        char[]buf = new char[1000000];
        int r = -1;
        int k= 0, l = 0;
        int d;
        
        while (true)
        {
            try{
                l = in.read(buf, 0, 1000000);
            }
            catch(Exception E){};
            
            for (int i=0; i<l; i++)
            {
                if (('0'<=buf[i])&&(buf[i]<='9'))
                {
                    if (r == -1)
                    {
                        r = 0;
                    }
                    d = buf[i] - '0';
                    r = 10 * r + d;
                }
                else
                {
                    if (r != -1)
                    {
                        x[k++] = r;
                    }
                    
                    r = -1;
                }
            }
            
            if (l<1000000)
                return;
        }
    }
    
    public void printArray(long[] a, int n)
    {
        printArray(a, n, ' ');
    }
    
    public void printArray(int[] a, int n)
    {
        printArray(a, n, ' ');
    }
            
    public void printArray(long[] a, int n, char dl)
    {
        long x; 
        int i, l = 0;
        for (i=0; i<n; i++)
        {
            x = a[i];
            
            if (x<0)
            {
                x = -x;
                l++;
            }
            
            if (x==0)
            {
                l++;
            }
            else
            {
                while (x>0)
                {
                    x /= 10;
                    l++;
                }
            }
        }
        
        l += n-1;
        
        char[] s = new char[l];
        
        l--;
        boolean z;
        for (i=n-1; i>=0;  i--)
        {
            x = a[i];
            z = false;            
            if (x<0)
            {
                x = -x;
                z = true;
            }
            
            do{
                s[l--] = (char)('0' + (x % 10));
                x /= 10;
            } while (x>0);
            
            if (z)
            {
                s[l--] = '-';
            }
            
            if (i>0)
            {
                s[l--] = dl;
            }
        }
        
        out.println(new String(s));
    }
    
    public void printArray(int[] a, int n, char dl)
    {
        int x; 
        int i, l = 0;
        for (i=0; i<n; i++)
        {
            x = a[i];
            
            if (x<0)
            {
                x = -x;
                l++;
            }
            
            if (x==0)
            {
                l++;
            }
            else
            {
                while (x>0)
                {
                    x /= 10;
                    l++;
                }
            }
        }
        
        l += n-1;
        
        char[] s = new char[l];
        
        l--;
        boolean z;
        for (i=n-1; i>=0;  i--)
        {
            x = a[i];
            z = false;            
            if (x<0)
            {
                x = -x;
                z = true;
            }
            
            do{
                s[l--] = (char)('0' + (x % 10));
                x /= 10;
            } while (x>0);
            
            if (z)
            {
                s[l--] = '-';
            }
            
            if (i>0)
            {
                s[l--] = dl;
            }
        }
        
        out.println(new String(s));
    }
    
    public void printMatrix(int[][] a, int n, int m)
    {
        int x; 
        int i,j, l = 0;
        for (i=0; i<n; i++)
        {
            for (j=0; j<m; j++)
            {
                x = a[i][j];
            
                if (x<0)
                {
                    x = -x;
                    l++;
                }

                if (x==0)
                {
                    l++;
                }
                else
                {
                    while (x>0)
                    {
                        x /= 10;
                        l++;
                    }
                }
            }
            
            l += m-1;
        }
        
        l += n-1;
        
        
        char[] s = new char[l];
        
        l--;
        boolean z;
        for (i=n-1; i>=0;  i--)
        {
            for (j=m-1; j>=0;  j--)
            {
                x = a[i][j];
                z = false;            
                if (x<0)
                {
                    x = -x;
                    z = true;
                }

                do{
                    s[l--] = (char)('0' + (x % 10));
                    x /= 10;
                } while (x>0);

                if (z)
                {
                    s[l--] = '-';
                }

                if (j>0)
                {
                    s[l--] = ' ';
                }
            }
            
            if (i>0)
            {
                 s[l--] = '\n';
            }
        }
        
        out.println(new String(s));
    }
    
    public void printMatrix(long[][] a, int n, int m)
    {
        long x; 
        int i,j, l = 0;
        for (i=0; i<n; i++)
        {
            for (j=0; j<m; j++)
            {
                x = a[i][j];
            
                if (x<0)
                {
                    x = -x;
                    l++;
                }

                if (x==0)
                {
                    l++;
                }
                else
                {
                    while (x>0)
                    {
                        x /= 10;
                        l++;
                    }
                }
            }
            
            l += m-1;
        }
        
        l += n-1;
        
        
        char[] s = new char[l];
        
        l--;
        boolean z;
        for (i=n-1; i>=0;  i--)
        {
            for (j=m-1; j>=0;  j--)
            {
                x = a[i][j];
                z = false;            
                if (x<0)
                {
                    x = -x;
                    z = true;
                }

                do{
                    s[l--] = (char)('0' + (x % 10));
                    x /= 10;
                } while (x>0);

                if (z)
                {
                    s[l--] = '-';
                }

                if (j>0)
                {
                    s[l--] = ' ';
                }
            }
            
            if (i>0)
            {
                 s[l--] = '\n';
            }
        }
        
        out.println(new String(s));
    }
    
    
}
