#include<stdio.h>

struct city_info {
	int city_num;
	int money;
	int road_num;
	int S_city[1500];
	int T_city[1500];
	int cost[1500];
	int time[1500];
	int ans;
};

struct city_info city;

void numin(int index, int numBox[1500]) {
	char str;
	for (int i = 0; i<index; i++)
		numBox[i] = 0;
	for (int i = 0; i<index; i++) {
		for (int j = 0;; j++) {
			str = getchar();
			if (str == '\n' && i == 0) {
				i = -1;
				break;
			}
			else if (str == '\n' && i != 0) {
				i = index;
				break;
			}
			else if (str < '0' || str > '9') {
				break;
			}
			else
				numBox[i] = numBox[i] * 10 + (int)str - (int)'0';
		}
	}
	return;
}


int search(int S_num, int cost, int timer) {
	for (int i = 0;i < city.city_num; i++) {
		if (city.S_city[i] == S_num) {
			cost += city.cost[i];
			timer += city.time[i];

			if (city.money < cost) {
				cost -= city.cost[i];
				timer -= city.time[i];
				break;
			}else if (city.T_city[i] == city.city_num) {
				if (timer < city.ans) {
					city.ans = timer;
				}
				cost -= city.cost[i];
				timer -= city.time[i];
				break;
			}else {
				search(city.T_city[i], cost, timer);
				cost -= city.cost[i];
				timer -= city.time[i];
			}
		}
	}
	return 0;
}

int main() {

	scanf("%d", &city.city_num);
	scanf("%d", &city.money);
	scanf("%d", &city.road_num);

	numin(city.road_num, city.S_city);
	numin(city.road_num, city.T_city);
	numin(city.road_num, city.cost);
	numin(city.road_num, city.time);
	city.ans = 1500001;

	search(1, 0, 0);

	if (city.ans == 1500001)
		printf("-1");
	else
		printf("%d", city.ans);

	return 0;
}