#include<bits/stdc++.h>
#define int long long
using namespace std;
signed main(){
    int N,K,P; cin>>N>>K>>P;
    vector<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.begin(),A.end());
    sort(B.begin(),B.end());
    int ok=P-1,ng=-1;
    while(ok-ng>1){
        int mid=(ok+ng)/2;
        int cnt=0;
        for(int i=0;i<N;i++){
            cnt+=upper_bound(B.begin(),B.end(),mid-A[i])-B.begin();
            cnt+=upper_bound(B.begin(),B.end(),mid+P-A[i])-lower_bound(B.begin(),B.end(),P-A[i]);
        }
        if(cnt>=K)ok=mid;
        else ng=mid;
    }
    cout<<ok<<endl;
}