#include<bits/stdc++.h> 
using namespace std;
typedef long long ll;
#define all(x) (x).begin(),(x).end()
template<typename T1,typename T2> bool chmin(T1 &a,T2 b){if(a<=b)return 0; a=b; return 1;}
template<typename T1,typename T2> bool chmax(T1 &a,T2 b){if(a>=b)return 0; a=b; return 1;}
int dx[4]={0,1,0,-1}, dy[4]={1,0,-1,0};
long double eps = 1e-9;
long double pi = acos(-1);


signed main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout << fixed << setprecision(20);

	int n,k,mod;
	cin>>n>>k>>mod;
	int a[n],b[n];
	for(int i=0;i<n;i++)cin>>a[i];
	for(int i=0;i<n;i++)cin>>b[i];
	sort(a,a+n);
	sort(b,b+n);
	int low = -1, up = 1e9+7, mid=-1;
	while(up-low>1){
		mid = (low + up) / 2;
		ll cnt = 0;
		for(int i=0;i<n;i++){
			cnt += lower_bound(b,b+n,mid-a[i]) - b;
			cnt += lower_bound(b,b+n,mid-a[i]+mod) - lower_bound(b,b+n,mod-a[i]);
		}
		if(cnt < k)low = mid;
		else up = mid;
	}
	cout << low << endl;
}