//
//  main.cpp
//  Q17
//
//  Created by AkihiroKOBAYASHI on 7/15/15.
//  Copyright (c) 2015 Akhr5884. All rights reserved.
//

#include <iostream>

int n, c, v;
int s[1600],t[1600],y[1600],m[1600];

int totaltime= -1;

int min(int a, int b) {
    if(a <= b) {
        return a;
    }
    return b;
}

void search(int start, int money, int time) {
    
    int count;
    
    if(start == n) {
        if(totaltime == -1) {
            totaltime = time;
        }
        else {
            totaltime = min(totaltime, time);
        }
        return;
    }
    
    for(count = 0; count < v; count++) {
        if(s[count] == start && money -  y[count] >= 0) {
            search(t[count], money - y[count], time + m[count]);
        }
    }
    return;
}

int main(int argc, const char * argv[]) {
    // insert code here...
    std::cin >> n >> c >> v;
    
    int count;
    
    for(count = 0; count < v; count++) {
        std::cin >> s[count];
    }

    for(count = 0; count < v; count++) {
        std::cin >> t[count];
    }

    for(count = 0; count < v; count++) {
        std::cin >> y[count];
    }

    for(count = 0; count < v; count++) {
        std::cin >> m[count];
    }
    
    search(1, c, 0);
    
    
    std::cout << totaltime << "\n";

    return 0;
}