n, k = map(int, input().split())
set1 = list(map(int, input().split()))
set2 = [i for i in range(1, k)]
c = 1
for i in set1:
    if i > k + c - 1:
        set2.append(i)
    elif i <= k:
        set2.append(k + c - 1)
        c += 1
set2 = set(set2)
def mex(Set):
    Set = list(Set)
    for i in range(1, max(Set) + 2):
        if i not in Set:
            return i
print(mex(set2))