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.DataInputStream; 
import java.io.FileInputStream; 
import java.io.IOException; 
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Scanner; 
import java.util.StringTokenizer; 
import java.io.BufferedReader; 
import java.util.*;
import java.math.BigInteger; 


public class C{
	public static FastReader fs = new FastReader();
	
	static PrintWriter out = new PrintWriter(System.out);
	
	static void solve() {
        StringBuffer output = new StringBuffer();
        int n = fs.nextInt();
        char bra []  = fs.next().toCharArray();
        int ans = 0;
        Stack<Character> st = new Stack<>();
        int last = -1;
        for(int i = 0; i<n; i++){
            if(last == -1){
                if(bra[i] == ')'){
                    if(!st.empty() && st.peek() == '(')st.pop();
                    else{
                        if(st.empty())last = i;
                        st.add('(');
                    }
                }
                else{
                    st.add('(');
                }
            }
            else{
                if(bra[i] == ')'){
                    st.add('(');
                }
                else{
                    st.pop();
                    if(st.empty()){
                        ans += (i-last + 1);
                        last = -1;
                    }
                }
            }
        }
        if(!st.empty())out.println(-1);
        else out.println(ans);
	}
	
	public static void main(String[] args) {
		int t = 1;
		//t = fs.nextInt();
		for(int cs = 1; cs <= t; cs++) {
			solve();
		}
		out.close();
	}
	
	static class FastReader 
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() 
        { 
            br = new BufferedReader(new
                     InputStreamReader(System.in)); 
        } 
  
        String next() 
        { 
            while (st == null || !st.hasMoreElements()) 
            { 
                try
                { 
                    st = new StringTokenizer(br.readLine()); 
                } 
                catch (IOException  e) 
                { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } 
  
        int nextInt() 
        { 
            return Integer.parseInt(next()); 
        } 
  
        long nextLong() 
        { 
            return Long.parseLong(next()); 
        } 
  
        double nextDouble() 
        { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() 
        { 
            String str = ""; 
            try
            { 
                str = br.readLine(); 
            } 
            catch (IOException e) 
            { 
                e.printStackTrace(); 
            } 
            return str; 
        } 
    } 
	
	static int ceil(int x,int y) {
		return (x % y == 0 ? x / y : (x / y +1));
	}
	
	static long ceil(long x,long y) {
		return (x % y == 0 ? x / y : (x / y +1));
	}
	
	static int max(int x,int y) {
		return Math.max(x, y);
	}
	
	static int min(int x,int y) {
		return Math.min(x, y);
	}
	
	static long max(long x,long y) {
		return Math.max(x, y);
	}
	
	static long min(long x,long y) {
		return Math.min(x, y);
	}
	
	static int min(int a []) {
		int x = 1_000_000_00_9;
		for(int i = 0; i<a.length; i++)x = min(x,a[i]);
		return x;
	}
	
	static int max(int a []) {
		int x = -1_000_000_00_9;
		for(int i = 0; i<a.length; i++)x = max(x,a[i]);
		return x;
	}
	
	static long min(long a []) {
		long x = (long)3e18;
		for(int i = 0; i<a.length; i++)x = min(x,a[i]);
		return x;
	}
	
	static long max(long a []) {
		long x = -(long)3e18;
		for(int i = 0; i<a.length; i++)x = max(x,a[i]);
		return x;
	}
	
	static int power(int x,int y) {
		int res = 1;
		while(y > 0) {
			if( y % 2 == 1)res = (res * x);
			y >>= 1;
            x = (x * x);
		}
		return res;
	}
	
	static long power(long x,long y) {
		long res = 1;
		while(y > 0) {
			if( y % 2 == 1)res = (res * x);
			y >>= 1;
            x = (x * x);
		}
		return res;
	}
	
	static long power(long x,long y,long mod) {
		long res = 1;
		x %= mod;
		while(y > 0) {
			if( y % 2 == 1)res = (res * x) % mod;
			y >>= 1;
            x = (x * x) % mod;
		}
		return res;
	}
	
	static void intsort(int [] a) {
		List<Integer> temp = new ArrayList<Integer>();
		for(int i = 0; i<a.length; i++)temp.add(a[i]);
		Collections.sort(temp);
		for(int i = 0; i<a.length; i++)a[i] = temp.get(i);
	}
	
	static void longsort(long [] a) {
		List<Long> temp = new ArrayList<Long>();
		for(int i = 0; i<a.length; i++)temp.add(a[i]);
		Collections.sort(temp);
		for(int i = 0; i<a.length; i++)a[i] = temp.get(i);
	}
	
	static void reverseintsort(int [] a) {
		List<Integer> temp = new ArrayList<Integer>();
		for(int i = 0; i<a.length; i++)temp.add(a[i]);
		Collections.sort(temp);
		Collections.reverseOrder();
		for(int i = 0; i<a.length; i++)a[i] = temp.get(i);
	}
	
	static void reverselongsort(long [] a) {
		List<Long> temp = new ArrayList<Long>();
		for(int i = 0; i<a.length; i++)temp.add(a[i]);
		Collections.sort(temp);
		Collections.reverseOrder();
		for(int i = 0; i<a.length; i++)a[i] = temp.get(i);
	}
	
	static void intpairsort(intpair [] a) {
		List<intpair> temp = new ArrayList<intpair>();
		for(int i = 0; i<a.length; i++)temp.add(a[i]);
		Collections.sort(temp,(p1,p2) -> {
			if(p1.x == p2.x) return p1.y >= p2.y ? -1 : 1;
			else return p1.x > p2.x ? -1 : 1;
		});
		for(int i = 0; i<a.length; i++)a[i] = temp.get(i);
	}
	
	static void longpairsort(longpair [] a) {
		List<longpair> temp = new ArrayList<longpair>();
		for(int i = 0; i<a.length; i++)temp.add(a[i]);
		Collections.sort(temp,(p1,p2) -> {
			if(p1.x == p2.x) return p1.y >= p2.y ? -1 : 1;
			else return p1.x > p2.x ? -1 : 1;
		});
		for(int i = 0; i<a.length; i++)a[i] = temp.get(i);
	}
	
	static class intpair{
		public int x;
		public int y;
		
		intpair(int a,int b){
			this.x = a;
			this.y = b;
		}
		
		intpair(){}
	}
	
	static class longpair{
		public long x;
		public long y;
		
		longpair(long a,long b){
			this.x = a;
			this.y = b;
		}
		
		longpair(){}
	}
	
	static class data{
		public long sum;
		
		data(long val){
		    this.sum = val;
		}
		
		data(){}
		
		data combine(data l, data r) {
		    data res = new data();
		    res.sum = l.sum + r.sum;
		    return res;
		}
	}
	
	static class Seg_Tree extends data{
		public int n;
		data [] seg;
		
		Seg_Tree(int sz){
			this.n = sz;
			seg = new data[4*n+4];
		}
		
		void build(long a[], int v, int tl, int tr) {
		    if (tl == tr) {
		        seg[v] = new data(a[tl]);
		    } else {
		        int tm = (tl + tr) / 2;
		        build(a, v*2, tl, tm);
		        build(a, v*2+1, tm+1, tr);
		        seg[v] = combine(seg[v*2],seg[v*2+1]);
		    }
		}

		void update(int v, int tl, int tr, int pos, long new_val) {
		    if (tl == tr) {
		        seg[v] = new data(new_val);
		    } else {
		        int tm = (tl + tr) / 2;
		        if (pos <= tm)
		            update(v*2, tl, tm, pos, new_val);
		        else
		            update(v*2+1, tm+1, tr, pos, new_val);
		        seg[v] = combine(seg[v*2],seg[v*2+1]);
		    }
		}
		
		data query(int v, int tl, int tr, int l, int r) {
		    if (l > r) 
		        return new data(0);
		    if (l == tl && r == tr) 
		        return seg[v];
		    int tm = (tl + tr) / 2;
		    return combine(query(v*2, tl, tm, l, min(r, tm)),query(v*2+1, tm+1, tr, max(l, tm+1), r));
		}
	}
	
	static class Bit_Tree{
		static int n;
		static int [] bit;
		
		Bit_Tree(int sz){
			Bit_Tree.n = sz;
			Bit_Tree.bit = new int[n+1];
		}
		
		static int child(int x) {
			return x + (x & (-x));
		}
		
		static int parent(int x) {
			return x - (x & (-x));
		}
		
		static void build(int [] a) {
			for(int i = 0; i<a.length; i++) {
				int start = i+1;
				while(start <= n) {
					bit[start] += a[i];
					start = child(start);
				}
			}
		}
		
		static void update(int idx,int new_val) {
			idx += 1;
			while(idx <= n) {
				bit[idx] += new_val;
				idx = child(idx);
			}
		}
		
		static int query(int right) {
			int res = 0;
			while(right > 0) {
				res += bit[right];
				right = parent(right);
			}
			return res;
		}
		
		static int query(int left,int right) {
			return query(right) - query(left-1);
		}
	}
	
	public static int gcd(int a, int b)  
    { 
        BigInteger b1 = BigInteger.valueOf(a); 
        BigInteger b2 = BigInteger.valueOf(b); 
        BigInteger gcd = b1.gcd(b2); 
            return gcd.intValue(); 
    } 
      
    public static long gcd(long a, long b)  
    { 
        BigInteger b1 = BigInteger.valueOf(a); 
        BigInteger b2 = BigInteger.valueOf(b); 
        BigInteger gcd = b1.gcd(b2); 
            return gcd.longValue(); 
    } 
}