package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)
var rdr = bufio.NewReaderSize(os.Stdin, 1000000)

func main() {
	sc.Split(bufio.ScanWords)
	stack := make([]rune, 0, 10000)
	indexes := make([]int, 10000)
	_, k := nextInt(), nextInt()
	index := 0

	for i, v := range nextLine() {
		if v == ')' {
			indexes[index] = i + 1
			indexes[i] = index + 1
			stack[index] = '*'
			stack = append(stack, '*')
			for j := index; j >= 0; j-- {
				if stack[j] == '(' {
					index = j
					break
				}
			}
			continue
		}
		index = i
		stack = append(stack, v)
	}

	fmt.Println(indexes[k-1])
}

func nextLine() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	i, _ := strconv.Atoi(nextLine())
	return i
}

func nextInt64() int64 {
	i, _ := strconv.ParseInt(nextLine(), 10, 64)
	return i
}

func nextUint64() uint64 {
	i, _ := strconv.ParseUint(nextLine(), 10, 64)
	return i
}

func nextFloat() float64 {
	f, _ := strconv.ParseFloat(nextLine(), 64)
	return f
}

func readLine() string {
	buf := make([]byte, 0, 1000000)
	for {
		l, p, e := rdr.ReadLine()
		if e != nil {
			panic(e)
		}
		buf = append(buf, l...)
		if !p {
			break
		}
	}
	return string(buf)
}