#include <stdio.h>

void merge_sort(int x[], int n)
{
	static int y[100001] = {};
	if (n <= 1) return;
	merge_sort(&(x[0]), n/2);
	merge_sort(&(x[n/2]), (n+1)/2);
	
	int i, p, q;
	for (i = 0, p = 0, q = n/2; i < n; i++) {
		if (p >= n/2) y[i] = x[q++];
		else if (q >= n) y[i] = x[p++];
		else y[i] = (x[p] < x[q])? x[p++]: x[q++];
	}
	for (i = 0; i < n; i++) x[i] = y[i];
}


int main()
{
	int i, N, P, A[100001], B[100001];
	long long K;
	scanf("%d %lld %d", &N, &K, &P);
	for (i = 0; i < N; i++) scanf("%d", &(A[i]));
	for (i = 0; i < N; i++) scanf("%d", &(B[i]));
	merge_sort(A, N);
	merge_sort(B, N);
	
	int l[2], r[2], m, L = 0, R = P - 1, M;
	long long tmp;
	while (L < R) {
		M = (L + R) / 2;
		for (i = 0, tmp = 0; i < N; i++) {
			if (A[i] > M) {
				l[0] = 0;
				r[0] = N;
				while (l[0] < r[0]) {
					m = (l[0] + r[0]) / 2;
					if (B[m] < P - A[i]) l[0] = m + 1;
					else r[0] = m;
				}
				l[1] = -1;
				r[1] = N - 1;
				while (l[1] < r[1]) {
					m = (l[1] + r[1] + 1) / 2;
					if (B[m] > P + M - A[i]) r[1] = m - 1;
					else l[1] = m;
				}
				tmp += l[1] - l[0] + 1;
			} else {
				l[0] = 0;
				r[0] = N;
				while (l[0] < r[0]) {
					m = (l[0] + r[0]) / 2;
					if (B[m] < P - A[i]) l[0] = m + 1;
					else r[0] = m;
				}
				l[1] = -1;
				r[1] = N - 1;
				while (l[1] < r[1]) {
					m = (l[1] + r[1] + 1) / 2;
					if (B[m] > M - A[i]) r[1] = m - 1;
					else l[1] = m;
				}
				tmp += N - l[0] + l[1] + 1;
			}
		}
		if (tmp < K) L = M + 1;
		else R = M;
	}
	printf("%d\n", L);
	fflush(stdout);
	return 0;
}