n, k = map(int, input().split())
s = input().strip()

# Adjust k to 0-based index
k -= 1

stack = []
pair = {}

for i in range(n):
    if s[i] == '(':
        stack.append(i)
    else:
        j = stack.pop()
        pair[j] = i
        pair[i] = j

# Find the corresponding pair
print(pair[k] + 1)  # Convert back to 1-based