#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for (int (i)=(0);(i)<(int)(n);++(i))
using ll = long long;

const int V = 50;
const int C = 301;
const int E = 1500;
const int inf = 1e8;

ll dp[V][C];
ll a[E], b[E], t[E], cost[E];

int main() {
    ll v, m, e;
    cin >> v >> m >> e;
    v--;

    rep(i, e) cin >> a[i], a[i]--;
    rep(i, e) cin >> b[i], b[i]--;
    rep(i, e) cin >> cost[i];
    rep(i, e) cin >> t[i];

    rep(i, V) rep(j, C) dp[i][j] = inf;
    dp[0][0] = 0;

    for (int i=0; i<v; ++i) {
        for (int j=0; j<e; ++j) {
            for (ll k=cost[j]; k<=m; ++k) {
                dp[b[j]][k] = min(dp[b[j]][k], dp[a[j]][k - cost[j]] + t[j]);
            }
        }
    }

    ll res = inf;
    rep(i, m+1) {
        res = min(res, dp[v][i]);
    }

    cout << (res == inf ? -1 : res) << endl;
}