#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;

typedef long long LL;

const int N = 1e6 + 5;

int n, m, a[N], b[N], tot, ans = 2e9;

struct Op{
	int x, op, id;
	bool operator < (const Op &b) const {
		return x < b.x;
	}
} e[N << 1];

int s = 0, need = 0, v1[N], v2[N];

void inline ins(int i) {
	int x = e[i].x, op = e[i].op, t = e[i].id;
	if (op == 1) {
		v1[t] = 1;
		if (!v2[t]) s++;
		else need--;
	} else if (op == 2) {
		v2[t] = 1;
		if (!v1[t]) s++, need++;
	}
}

void inline del(int i) {
	int x = e[i].x, op = e[i].op, t = e[i].id;
	if (op == 1) {
		v1[t] = 0;
		if (!v2[t]) s--;
		else need++;
	} else if (op == 2) {
		v2[t] = 0;
		if (!v1[t]) s--, need--;
	}
}

bool inline check() {
	return s == n && need <= m;
}

bool inline ok(int i) {
	del(i);
	if (check()) return true;
	else {
		ins(i);
		return false;
	}
}

int main() {
	//freopen("card.in", "r", stdin);
	//freopen("card.out", "w", stdout);
	scanf("%d%d", &n, &m);
	for (int i = 1; i <= n; i++) scanf("%d", a + i), e[++tot] = (Op) { a[i], 1, i };
	for (int i = 1; i <= n; i++) scanf("%d", b + i), e[++tot] = (Op) { b[i], 2, i };
	sort(e + 1, e + 1 + tot);
	for (int i = 1, j = 1; i <= tot; i++) {
		ins(i);
		while (j < i && ok(j)) j++;
		if (check()) ans = min(ans, e[i].x - e[j].x);	
	}
	printf("%d\n", ans);
}