from bisect import bisect_left, bisect_right
import sys
def main():
    input = sys.stdin.readline
    N, K, P = map(int, input().split())
    *A, = map(int, input().split())
    *B, = map(int, input().split())
    A.sort()
    B.sort()

    # x以下の要素の数
    def f(x):
        res = 0
        for a in A:
            # Ai+Bj <= x
            if a + B[0] <= x:
                i = bisect_right(B, x - a)
                res += i
            # P <= Ai+Bi <= P+x
            if a + B[0] <= P + x:
                i = bisect_left(B, P - a)
                j = bisect_right(B, P + x - a)
                res += max(0, j - i)
        return res

    l = -1
    r = P-1
    while r - l > 1:
        m = (l + r) // 2
        if f(m) < K: l = m
        else: r = m
    print(r)

if __name__ == '__main__':
    main()