#include<iostream>
#include<algorithm>
using namespace std;
int N,P;
long K;
int A[1<<17],B[1<<17];
long cnt(int X)
{
	long ans=0;
	for(int i=0;i<N;i++)
	{
		if(A[i]<X)
		{
			ans+=lower_bound(B,B+N,X-A[i])-B;
		}
		ans+=lower_bound(B,B+N,P+X-A[i])-lower_bound(B,B+N,P-A[i]);
	}
	return ans;
}
main()
{
	cin>>N>>K>>P;
	for(int i=0;i<N;i++)cin>>A[i];
	for(int i=0;i<N;i++)cin>>B[i];
	sort(B,B+N);
	int L=0,R=P;
	while(R-L>1)
	{
		int mid=(L+R)/2;
		if(cnt(mid)>=K)R=mid;
		else L=mid;
	}
	cout<<L<<endl;
}