#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
//#include "temp.cpp"
#include <cstdio>
using namespace std;
#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif
#define sz(x) (int)x.size()
#define len(x) (int)x.length()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(x) (x).clear()
#define uniq(x) x.resize(unique(all(x)) - x.begin());
#define blt __builtin_popcount
#define pb push_back
#define popf pop_front
#define popb pop_back
#define ld long double
#define ll long long
void print(long long t) {cerr << t;}
void print(int t) {cerr << t;}
void print(string t) {cerr << t;}
void print(char t) {cerr << t;}
void print(double t) {cerr << t;}
void print(long double t) {cerr << t;}
void print(unsigned long long t) {cerr << t;}
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'
// Indexed Set
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(T v[],V n) {cerr << "["; for(int i = 0; i < n; i++) {print(v[i]); cerr << " "; } cerr << "]";}
template <class T, class V> void print(pair <T, V> p) {cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}";}
template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
// template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(set <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(multiset <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(Tree <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void print(map <T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(deque <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
// for random generations
mt19937 myrand(chrono::steady_clock::now().time_since_epoch().count());
// mt19937 myrand(131);
// for grid problems
int dx[8] = {-1,0,1,0,1,-1,1,-1};
int dy[8] = {0,1,0,-1,1,1,-1,-1};
// lowest / (1 << 17) >= 1e5 / (1 << 18) >= 2e5 / (1 << 21) >= 1e6
void fastIO() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr); cout.tie(nullptr);
}
// file in/out
void setIO(string str = "") {
fastIO();
if(str == "input") {
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
} else if(str != "") {
freopen((str + ".in").c_str(), "r", stdin);
freopen((str + ".out").c_str(), "w", stdout);
}
}
const long long inf = 1e16;
const int N = 385, M = 55;
vector<pair<long long, long long>> adj[N];
long long s[N][N], b[N][N];
long long dist[N][N];
int n, m, k;
long long dp[M][M][2 * M];
void solve_() {
cin >> n >> m >> k;
int flag = 1;
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= k; j++) {
cin >> b[i][j] >> s[i][j];
if(i > 1 && b[i][j] != -1) {
flag = false;
}
}
}
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= n; j++) {
dist[i][j] = inf;
}
dist[i][i] = 0;
}
for(int i = 1; i <= m; i++) {
long long u, v, k; cin >> u >> v >> k;
dist[u][v] = min(dist[u][v], k);
adj[u].emplace_back(v, k);
}
for (int k = 1; k <= n; k++)
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++)
dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j]);
if(flag) {
long long answ = 0;
for(int i = 1; i <= k; i++) {
if(b[1][i] != -1) {
for(int j = 2; j <= n; j++) {
if(s[j][i] > b[1][i]) {
answ = max(answ, (s[j][i] - b[1][i]) / (dist[1][j] + dist[j][1]));
}
}
}
}
cout << answ << '\n';
} else if(max(n, k) <= 50) {
long long answ = 0;
for(int start = 1; start <= n; start++) {
// memset(dp, -1, sizeof(dp));
for(int i = 0; i <= n; i++) {
for(int j = 0; j <= k; j++) {
for(int e = 0; e <= 2 * n; e++) {
dp[i][j][e] = -inf;
}
}
}
dp[start][0][0] = 0;
for(int key = 1; key <= k; key++) {
if(b[start][key] != -1) {
dp[start][key][0] = -b[start][key];
}
}
for(int time = 0; time < 2 * n; time++) {
for(int curr = 1; curr <= n; curr++) {
for(int key = 0; key <= k; key++) {
if(dp[curr][key][time] == -inf) continue;
for(auto to: adj[curr]) {
if(key != 0 && s[to.first][key] != -1) {
dp[to.first][0][time + 1] = max(dp[to.first][0][time + 1], dp[curr][key][time] + s[to.first][key]);
}
if(key == 0) {
for(int new_key = 1; new_key <= k; new_key++) {
if(b[to.first][new_key] != -1) {
dp[to.first][new_key][time + 1] = max(dp[to.first][new_key][time + 1], dp[curr][key][time] - b[to.first][new_key]);
}
}
}
dp[to.first][key][time + 1] = max(dp[to.first][key][time + 1], dp[curr][key][time]);
}
}
}
}
for(int time = 1; time <= 2 * n; time++) {
answ = max(answ, dp[start][0][time] / time);
}
}
cout << answ << '\n';
}
}
int main() {
setIO();
auto solve = [&](int test_case)-> void {
for(int i = 1; i <= test_case; i++) {
solve_();
}
};
int test_cases = 1;
// cin >> test_cases;
solve(test_cases);
return 0;
}
