import sys
input = sys.stdin.readline

def judge(x):
    cnt = 0
    
    for Ai in A:
        if x>=Ai:
            cnt += acc[x-Ai+1]+acc[P]-acc[P-Ai]
        else:
            cnt += acc[P-Ai+x+1]-acc[P-Ai]
    
    return cnt>=K
            
def binary_search():
    l, r = 0, P-1
    
    while l<=r:
        m = (l+r)//2
        
        if judge(m):
            r = m-1
        else:
            l = m+1
    
    return l

N, K, P = map(int, input().split())
A = list(map(int, input().split()))
B = list(map(int, input().split()))
C = [0]*P

for Bi in B:
    C[Bi] += 1

acc = [0]

for Ci in C:
    acc.append(acc[-1]+Ci)

print(binary_search())