#pragma GCC optimize ("Ofast")
//#pragma GCC target ("avx2")
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ll long long
#define ld long double
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define ii pair<int, int>
#define ff first
#define ss second
#define mp make_pair
#define UB upper_bound
#define LB lower_bound
#define pb push_back
#define vi vector<int>
#define vvi vector<vi>
#define vb vector<bool>
#define vvb vector<vb>
#define vs vector<string>
#define vii vector<ii>
#define vvii vector<vii>
#define vll vector<ll>
#define vld vector<ld>
const int N = 101, K = 1001;
int n, m, k, ans;
vii adj[N];
bool vis[N][N];
int p[N];
int buy[N][K];
int sell[N][K];
vi cycle;
int best(int idx, int x, int sum) { // en que idx estoy, que objeto llevo, cuanto dinero llevo
if (idx == cycle.size()) return sum;
int u = cycle[idx];
int mx = 0;
// en este nodo no hago nada
mx = max(mx, best(idx+1, x, sum));
if (x != -1) {
// lo puedo vender?
int s = sell[u][x];
if (s != -1) mx = max(mx, best(idx, -1, sum + s));
}
for (int i = 0; i < k; i++) {
// lo puedo comprar?
int b = buy[u][i];
if (b != -1) mx = max(mx, best(idx+1, i, sum - b));
}
return mx;
}
void dfs(int u, int par, int d, int s) {
vis[par][u] = 1;
p[u] = par;
for (auto &[v, w] : adj[u]) {
if (vis[u][v]) continue;
if (v == s) {
cycle.clear();
cycle.pb(s);
while (u != s) {
cycle.pb(u);
u = p[u];
}
cycle.pb(s);
reverse(all(cycle));
ans = max(ans, best(0, -1, 0) / (d+w));
}
else dfs(v, u, d+w, s);
}
vis[par][u] = 1;
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
ans = 0;
cin >> n >> m >> k;
for (int i = 0; i < n; i++) {
for (int j = 0; j < k; j++) {
int b, s;
cin >> b >> s;
buy[i][j] = b;
sell[i][j] = s;
assert(buy[i][j] >= sell[i][j]);
}
}
while (m--) {
int x, y, z;
cin >> x >> y >> z;
x--; y--;
adj[x].pb(mp(y, z));
}
for (int i = 0; i < n; i++) {
dfs(i, i, 0, i);
}
cout << ans << "\n";
return 0;
}
