def main():
    n, k = map(int, input().split())
    s = input()
    ans = solve(n, k, s)
    print(ans)


def solve(n, k, s):
    ar = {}
    s = list(s)
    for i in range(n):
        if s[i] == ')':
            for j in range(i - 1, -1, -1):
                if s[j] == '(':
                    s[j] = '*'
                    i, j = i + 1, j + 1
                    ar[i] = j
                    ar[j] = i
                    #print(i, j)
                    break
    #print(ar)
    return ar[k]


if __name__ == '__main__':
    main()