package main

import (
	"fmt"
)

func resolve(N, K int, S string) int {
	result := make([]int, N)
	for i := 0; i < N; i++ {
		if S[i] == '(' {
			continue
		}
		for j := i - 1; j >= 0; j-- {
			if result[j] != 0 {
				continue
			}
			result[j] = i + 1
			result[i] = j + 1
			break
		}
	}
	return result[K-1]
}

func main() {
	var N, K int
	var S string
	fmt.Scanf("%d %d\n%s\n", &N, &K, &S)
	fmt.Println(resolve(N, K, S))
}