package main

import . "fmt"

func main() {
	var n,k int
	var s string
	Scan(&n,&k,&s)
	p := make([]int, n)
	t := make([]int, 0, n)
	for i,r := range s {
		switch r {
			case '(':
				t=append(t,i)
			case ')':
				x := len(t)
				j:=t[x-1]
				t=t[:x-1]
				p[i],p[j]=j+1,i+1
		}
	}
	Println(p[k-1])
}