#include <iostream>
#include <queue>
#include <tuple>
#include <utility>
#include <vector>
struct Edge {
int to;
long long length, profit;
};
int main() {
int n, m, k;
std::cin >> n >> m >> k;
std::vector<std::vector<long long>> b(n, std::vector<long long>(k)), s(n, std::vector<long long>(k));
for (int i = 0; i < n; ++i) {
for (int item = 0; item < k; ++item) std::cin >> b[i][item] >> s[i][item];
}
std::vector<std::vector<Edge>> adj(n);
while (m--) {
int u, v, t;
std::cin >> u >> v >> t;
--u, --v;
adj[u].emplace_back(v, t, 0);
}
std::vector<std::vector<long long>> shortestPath(n, std::vector<long long>(n));
for (int i = 0; i < n; ++i) {
std::priority_queue<std::pair<long long, int>> q;
std::vector<int> seen(n);
q.emplace(0, i);
while (!q.empty()) {
auto [d, node] = q.top();
q.pop();
if (seen[node]) continue;
shortestPath[i][node] = -d;
seen[node] = true;
for (auto e : adj[node]) {
q.emplace(d - e.length, e.to);
}
}
}
for (int i = 0; i < n; ++i) {
for (int f = 0; f < n; ++f) {
if (i == f) continue;
long long max = 0;
for (int item = 0; item < k; ++item) {
if (b[i][item] == -1 || s[i][item] == -1) continue;
max = std::max(max, s[f][item] - b[i][item]);
}
if (max) {
adj[i].emplace_back(f, shortestPath[i][f], max);
}
}
}
long long max = 0;
for (int i = 0; i < n; ++i) {
std::queue<std::tuple<int, long long, long long, int>> q;
q.emplace(i, 0, 0, 0);
while (!q.empty()) {
auto [node, dist, profit, littledist] = q.front();
q.pop();
if (littledist > n) break;
if (node == i) {
max = std::max(max, profit / dist);
}
for (auto e : adj[node]) {
q.emplace(e.to, dist + e.length, profit + e.profit, littledist + 1);
}
}
}
std::cout << max << '\n';
}
