n, k = gets.split.map(&:to_i)
s = gets

stack = []
ans = []
s.each_char.with_index do |c, idx|
    stack.push(idx) if c == "("
    ans = [stack.pop + 1, idx + 1] if c == ")"
    
    if ans[0] == k
        puts ans[1]
        exit 0
    end
    if ans[1] == k
        puts ans[0] 
        exit 0
    end
end