#include <bits/stdc++.h>
using namespace std;

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

int main() {
    int N, C, V;
    cin >> N >> C >> V;

    vector<vector<Edge>> graph(N);
    for (int i = 0; i < V; i++) {
        int s, t, y, m;
        cin >> s >> t >> y >> m;
        s--, t--;
        graph[s].push_back({t, y, m});
    }

    vector<int> dp(C+1, INT_MAX);
    dp[0] = 0;

    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<>> pq;
    pq.push({0, 0});

    while (!pq.empty()) {
        auto [curr_time, curr_cost] = pq.top();
        pq.pop();

        if (curr_time > dp[curr_cost]) continue;

        for (const auto& [to, cost, time] : graph[0]) {
            int new_cost = curr_cost + cost;
            int new_time = curr_time + time;

            if (new_cost <= C && new_time < dp[new_cost]) {
                dp[new_cost] = new_time;
                pq.push({new_time, new_cost});
            }
        }
    }

    int ans = *min_element(dp.begin(), dp.end());
    cout << (ans == INT_MAX ? -1 : ans) << endl;

    return 0;
}