#include <bits/stdc++.h>
#ifdef DEBUG
#include "cpp-dump/dump.hpp"
#define dump(...) cpp_dump(__VA_ARGS__)
#else
#define dump(...)
#endif
using namespace std;
typedef long long ll;

void solve() {
    ll n,k;
    cin >> n >> k;
    vector<ll> A(n), B(n), C(n);
    for (ll i = 0; i < n; ++i) cin >> A[i];
    for (ll i = 0; i < n; ++i) cin >> B[i];
    for (ll i = 0; i < n; ++i) cin >> C[i];

    vector<vector<ll>> dp(n+3, vector<ll>(k+3,0));
    dp[0][0] = 0;
    
    // i本目までj個塩でトッピングするときの最大値
    for (ll i = 0; i < n; ++i) {
        for (ll j = 0; j < k; ++j) {
            if (j > i) continue;

            dp[i+1][j] = max(dp[i+1][j], dp[i][j]+A[i]+C[i]);
            dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j]+A[i]+B[i]);
        }
    }
    dump(dp);

    cout << dp[n][k] << endl;
}

int main() {
    solve();
    return 0;
}