#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint1000000007;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000001

int main(){
	
	long long N,K,P;
	cin>>N>>K>>P;
	
	vector<long long> A(N),B(N);
	rep(i,N)cin>>A[i];
	rep(i,N)cin>>B[i];
	
	sort(A.begin(),A.end());
	sort(B.begin(),B.end());
	
	long long ng = -1,ok = P;
	
	while(ok-ng>1){
		long long mid = (ok+ng)/2;
		
		long long cnt = 0LL;
		
		rep(i,N){
			if(A[i]<=mid){
				cnt += distance(B.begin(),upper_bound(B.begin(),B.end(),mid-A[i]));
				cnt += distance(lower_bound(B.begin(),B.end(),P-A[i]),upper_bound(B.begin(),B.end(),P-1));
			}
			else{
				cnt += distance(lower_bound(B.begin(),B.end(),P-A[i]),upper_bound(B.begin(),B.end(),P-(A[i]-mid)));
			}
		}
		
		
		if(cnt>=K)ok = mid;
		else ng = mid;
		
	}
	
	cout<<ok<<endl;
	
	
	return 0;
}