from bisect import bisect_right
n, k, p = map(int, input().split())
a = list(map(int, input().split()))
b = list(map(int, input().split()))
a.sort()
b.sort()
l, r = -1, p - 1
for j in range(n):
    m = (l + r) // 2
    t = 0
    for i in range(n):
        t += bisect_right(b, p + m - a[i]) - bisect_right(b, p - 1 - a[i]) + bisect_right(b, m - a[i])
    if t >= k:
        r = m
    else:
        l = m
print(r)