#include <iostream>
#include <vector>
#include <algorithm>
#include <climits>
using namespace std;

const int INF = 1e9;

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

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    
    int N, C, V;
    cin >> N >> C >> V;
    
    vector<Edge> edges;
    edges.reserve(V);
    vector<int> graph_start(N + 1, 0);
    
    // Read all input first for better performance
    vector<int> input(4 * V);
    for (int i = 0; i < 4 * V; i++) {
        cin >> input[i];
    }
    
    // Count edges per node using reference
    for (int i = 0; i < V; i++) {
        int& s = input[i];
        graph_start[s]++; // s is 1-indexed
    }
    
    // Convert counts to start indices (prefix sum)
    for (int i = 1; i <= N; i++) {
        graph_start[i] += graph_start[i - 1];
    }
    
    // Store edges using direct memory access
    vector<Edge> graph_edges(V);
    vector<int> edge_count(N + 1, 0);
    
    for (int i = 0; i < V; i++) {
        int& s = input[i];
        int& t = input[V + i];
        int& cost = input[2 * V + i];
        int& time = input[3 * V + i];
        
        int pos = graph_start[s - 1] + edge_count[s]++;
        graph_edges[pos] = {t - 1, cost, time};
    }
    
    // DP array with reference optimization
    vector<vector<int>> dp(N, vector<int>(C + 1, INF));
    dp[0][C] = 0;
    
    // Use references and direct pointer access for maximum speed
    for (int i = 0; i < N; i++) {
        int start_idx = graph_start[i];
        int end_idx = graph_start[i + 1];
        int edge_count = end_idx - start_idx;
        
        if (edge_count == 0) continue;
        
        // Get pointer to the first edge for this node
        const Edge* edges_ptr = graph_edges.data() + start_idx;
        
        for (int k = C; k >= 0; k--) {
            int& current_dp = dp[i][k];
            if (current_dp == INF) continue;
            
            // Process all edges using pointer arithmetic
            for (int j = 0; j < edge_count; j++) {
                const Edge& e = edges_ptr[j];
                if (k >= e.cost) {
                    int& target = dp[e.to][k - e.cost];
                    int new_time = current_dp + e.time;
                    if (new_time < target) {
                        target = new_time;
                    }
                }
            }
        }
    }
    
    // Find minimum result using reference
    int result = INF;
    const vector<int>& last_node = dp[N - 1];
    for (int k = 0; k <= C; k++) {
        const int& val = last_node[k];
        if (val < result) {
            result = val;
        }
    }
    
    cout << (result == INF ? -1 : result) << endl;
    
    return 0;
}