#include <bits/stdc++.h>

using namespace std;

#define LOG(...) fprintf(stderr,__VA_ARGS__)
//#define LOG(...)
#define FOR(i,a,b) for(int i=(int)(a);i<(int)(b);++i)
#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort(ALL(c))
#define RSORT(c) sort(RALL(c))

typedef long long ll;
typedef unsigned long long ull;
typedef vector<bool> vb;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vb> vvb;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

struct P {
    int town, time, money;

    bool operator >(const P& p) const {
        return time > p.time;
    }
};

struct Edge {
    int to, cost, time;
};

int main() {
    int town_n, money, road_n;
    cin >> town_n >> money >> road_n;
    vi from(road_n+1), to(road_n+1), cost(road_n+1), time(road_n+1);
    REP(i, road_n) cin >> from[i];
    REP(i, road_n) cin >> to[i];
    REP(i, road_n) cin >> cost[i];
    REP(i, road_n) cin >> time[i];
    vector<vector<Edge>> E(town_n+1);
    REP(i, road_n) {
        E[from[i]].push_back({to[i], cost[i], time[i]});
    }

    priority_queue<P, vector<P>, greater<P>> que;
    que.push({1, 0, money});
    while (!que.empty()) {
        P p = que.top(); que.pop();

        if (p.town == town_n) {
            cout << p.time << endl;
            return 0;
        }

        for (Edge& e : E[p.town]) {
            int money = p.money - e.cost;
            if (money >= 0) {
                que.push({e.to, p.time + e.time, money});
            }
        }
    }

    cout << -1 << endl;
}