#include<bits/stdc++.h>
using namespace std;

int main(){
    int N,K;
    int A[N],B[N];
    scanf("%d%d",&N,&K);
    for (int i=0; i<N; i++){
        scanf("%d",&A[i]);
    }
    for (int i=0; i<N; i++){
        scanf("%d",&B[i]);
    }
    sort(A,A+N); reverse(A,A+N);
    sort(B,B+N); reverse(B,B+N);
    if (A[0] > B[0]){
        cout << A[0] + B[K-1] << "\n";
    }
    else{
        cout << B[0] + A[K-1] << "\n";
    }
    return 0;
}