#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
#define N 1000005 
#define int long long
#define fo(i,l,r) for(int i=l;i<=r;i++)
#define rf(i,r,l) for(int i=r;i>=l;i--)
using namespace std;
int n,m,ans,x,y,z;bool ha[N],hb[N];
struct node{int i,op,x;bool operator<(node y){return x<y.x;}}a[N<<1]; 
void swap(int &x,int &y){int t=x;x=y;y=t;}
int max(int x,int y){return x>y?x:y;}
int min(int x,int y){return x<y?x:y;}
bool ck(int x)
{
    for(int i=1;i*2<=n;i++)ha[i]=hb[i]=0;
    int s1=0,s2=0;
    for(int i=1,j=1;j<=n;j++)
    {
        if(!ha[a[j].i]&&!hb[a[j].i])s1++;
        if(!ha[a[j].i]&&!hb[a[j].i]&&a[j].op==1)s2++;
        if(!ha[a[j].i]&&hb[a[j].i])s2--;
        if(!a[j].op)ha[a[j].i]=1;if(a[j].op==1)hb[a[j].i]=1;
        while(i<j&&a[j].x-a[i].x>x)
        {
            if(!ha[a[i].i]||!hb[a[i].i])s1--;
            if(ha[a[i].i]&&hb[a[i].i]&&!a[i].op)s2++;
            if(!ha[a[i].i]&&hb[a[i].i])s2--;
            if(!a[i].op)ha[a[i].i]=0;if(a[i].op==1)hb[a[i].i]=0;
            i++; 
        }
        if(a[j].x-a[i].x<=x&&s1*2==n&&s2<=m)return 1;
    }
    return 0;
}
int read(){
    int sum=0;bool f=0;char c=getchar();
    for(;c<48||c>57;c=getchar())if(c==45)f=1;
    for(;c>=48&&c<=57;c=getchar())sum=sum*10+(c&15);
    return f?-sum:sum;
}
signed main(){
    freopen("card.in","r",stdin);freopen("card.out","w",stdout);
    n=read();m=read();
    fo(i,1,n)a[i*2-1]={i,0,read()};
    fo(i,1,n)a[i*2]={i,1,read()};
    n<<=1;
    sort(a+1,a+n+1);
    int l=1,r=1e9,mid;
    while(l<r)
    {
        mid=l+r>>1;
        if(ck(mid))r=mid;
        else l=mid+1;
    }
    printf("%lld",l);
    return 0;
}