from bisect import *
N,K,P=map(int,input().split())
A=list(map(int,input().split()))
A.sort(reverse=True)
B=list(map(int,input().split()))
B.sort()
L,R=0,P
while L<R:
  M=(L+R)>>1
  C=0
  x,y,z=0,0,0
  for i in range(N):
    while x<N and B[x]<=M-A[i]:
      x+=1
    while y<N and B[y]<=P+M-A[i]:
      y+=1
    while z<N and B[z]<P-A[i]:
      z+=1
    if M>=A[i]:
      C+=x+y-z
    else:
      C+=y-z
  if C>=K:
    R=M
  else:
    L=max(L+1,M)
print(L)