n, k = map(int, input().split())
a = list(input())
d = []
rec = []
for i, v in enumerate(a):
    if v == "(":
        d.append(i+1)
    elif v == ")":
        p = d.pop()
        rec.append((p, i+1))
#print(rec)
if a[k-1] == "(":
    for key, val in rec:
        if key == k:
            print(val)
            break
else:
    for key, val in rec:
        if val == k:
            print(key)
            break