#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <cmath>
#include <vector>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <queue>
#include <ctime>
#include <cassert>
#include <complex>
#include <string>
#include <cstring>
#include <chrono>
#include <random>
#include <bitset>
#include <fstream>
using namespace std;
#define int long long
#define ii pair <int, int>
#define app push_back
#define all(a) a.begin(), a.end()
#define bp __builtin_popcountll
#define ll long long
#define mp make_pair
#define x first
#define y second
#define Time (double)clock()/CLOCKS_PER_SEC
#define debug(x) std::cerr << #x << ": " << x << '\n';
#define FOR(i, n) for (int i = 0; i < n; ++i)
#define FORN(i, n) for (int i = 1; i <= n; ++i)
#define pb push_back
#define trav(a, x) for (auto& a : x)
using vi = vector<int>;
template <typename T>
std::istream& operator >>(std::istream& input, std::vector<T>& data)
{
for (T& x : data)
input >> x;
return input;
}
template <typename T>
std::ostream& operator <<(std::ostream& output, const pair <T, T> & data)
{
output << "(" << data.x << "," << data.y << ")";
return output;
}
template <typename T>
std::ostream& operator <<(std::ostream& output, const std::vector<T>& data)
{
for (const T& x : data)
output << x << " ";
return output;
}
ll div_up(ll a, ll b) { return a/b+((a^b)>0&&a%b); } // divide a by b rounded up
ll div_down(ll a, ll b) { return a/b-((a^b)<0&&a%b); } // divide a by b rounded down
ll math_mod(ll a, ll b) { return a - b * div_down(a, b); }
#define tcT template<class T
#define tcTU tcT, class U
tcT> using V = vector<T>;
tcT> void re(V<T>& x) {
trav(a, x)
cin >> a;
}
tcT> bool ckmin(T& a, const T& b) {
return b < a ? a = b, 1 : 0;
} // set a = min(a,b)
tcT> bool ckmax(T& a, const T& b) {
return a < b ? a = b, 1 : 0;
}
ll gcd(ll a, ll b) {
while (b) {
tie(a, b) = mp(b, a % b);
}
return a;
}
const int N = 107, K = 1007, INF = 1e18;
int n, m, k;
int buy[N][K], sell[N][K];
int dist[N][N], earn[N][N];
int dp[N][N];
signed main() {
#ifdef LOCAL
#else
#define endl '\n'
ios_base::sync_with_stdio(0); cin.tie(0);
#endif
cin >> n >> m >> k;
FOR (i, n) {
FOR (j, k) {
cin >> buy[i][j] >> sell[i][j];
}
}
FOR (i, n) FOR (j, n) dist[i][j] = INF;
FOR (i, m) {
int u, v, c;
cin >> u >> v >> c;
u--; v--;
ckmin(dist[u][v], c);
}
FOR (k, n) {
FOR (u, n) {
FOR (v, n) {
ckmin(dist[u][v], dist[u][k] + dist[k][v]);
}
}
}
FOR (u, n) {
FOR (v, n) {
FOR (i, k) {
if (sell[v][i] != -1 && buy[u][i] != -1) {
ckmax(earn[u][v], sell[v][i] - buy[u][i]);
}
}
}
}
auto check = [&] (int w) {
FOR (u, n) {
FOR (v, n) {
if (dist[u][v] == INF) {
dp[u][v] = INF;
}
else {
dp[u][v] = dist[u][v] * w - earn[u][v];
}
}
}
FOR (k, n) {
FOR (u, n) {
FOR (v, n) {
ckmin(dp[u][v], dp[u][k] + dp[k][v]);
if (dp[u][v] < -INF) {
return 1;
}
}
}
}
FOR (u, n) {
if (dp[u][u] <= 0) {
return 1;
}
}
return 0;
};
int l = 0, r = 1e9+7;
while (l < r - 1) {
int m = (l + r) / 2;
if (check(m))
l = m;
else
r = m;
}
cout << l << endl;
}
