import numpy as np

n, k, p = map(int, input().split())
A = np.array(input().split(), np.int64)
B = np.array(input().split(), np.int64)
A = np.sort(A)
B = np.sort(B)

def is_ok(x):
    cnt = 0
    cnt += np.searchsorted(B, x-A, side='right').sum()
    cnt += np.searchsorted(B, p+x-A, side='right').sum()
    cnt -= np.searchsorted(B, p-A, side='left').sum()
    return cnt >= k

ng = -1
ok = p
while ng+1 < ok:
    c = (ng+ok)//2
    if is_ok(c):
        ok = c
    else:
        ng = c
print(ok)