#include <iostream>
#include <algorithm>
#include <functional>
#include <string>
#include <limits.h>
using namespace std;

int city_max,money_max,root_max;
int from[1500],to[1500],moneyd[1500],timed[1500];

int func(int now, int money, int time){
	int min_time = 999999999;
	int result;
	
	//現在地がゴールなら、所要時間を返す
	if(now == city_max){
		return time;
	}
	
	//そうでなければ道を探す
	for(int i=0; i<root_max; i++){
		if(from[i] == now){
			if(money - moneyd[i] >= 0){
				result = func(to[i], money - moneyd[i], time + timed[i]);
				if(result != -1 && result < min_time){
					min_time = result;
				}
			}
		}
	}
	
	//結果を返す
	if(result == 999999999){
		return -1;
	}else{
		return min_time;
	}
}

int main(){

	int ans;
	cin >> city_max >> money_max >> root_max;
	for(int i=0; i<root_max; i++){
		cin >> from[i];
	}
	for(int i=0; i<root_max; i++){
		cin >> to[i];
	}
	for(int i=0; i<root_max; i++){
		cin >> moneyd[i];
	}
	for(int i=0; i<root_max; i++){
		cin >> timed[i];
	}
	
	cout << func(1, money_max, 0) << endl;
	
	return 0;
}