#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define pii pair <int, int>
#define ff first
#define ss second
#define sz size()
const int N = 1e2 + 5;
const int K = 1e3 + 5;
int buy[N][K], sell[N][K], n, m, d;
ll val[N][N], dis[N][N], profit[N][N];
ll INF = 1e10;
bool check (int x) {
// jog - x * time >= 0
for (int i = 1; i <= n; ++i) {
for (int j = 1; j <= n; ++j) {
if (dis[i][j] != INF) {
val[i][j] = profit[i][j] - x * dis[i][j];
}
else val[i][j] = -INF;
}
}
for (int k = 1; k <= n; ++k) {
for (int i = 1; i <= n; ++i) {
for (int j = 1; j <= n; ++j) {
if (i == j) continue;
val[i][j] = max (val[i][j], val[i][k] + val[k][j]);
}
}
}
for (int i = 1; i <= n; ++i) {
for (int j = 1; j <= n; ++j) {
if (i == j) continue;
if (dis[i][j] != INF and dis[j][i] != INF)
if (val[i][j] + val[j][i] >= 0) {
return 1;
}
}
}
return 0;
}
int main () {
// freopen ("input.txt", "r", stdin);
cin >> n >> m >> d;
for (int i = 1; i <= n; ++i) {
for (int j = 1; j <= d; ++j) {
cin >> buy[i][j] >> sell[i][j];
}
}
for (int i = 1; i <= n; ++i) {
for (int j = 1; j <= n; ++j) {
dis[i][j] = INF;
if (i == j) dis[i][j] = 0;
}
}
for (int i = 1; i <= m; ++i) {
int l, r, w;
cin >> l >> r >> w;
dis[l][r] = w;
}
for (int k = 1; k <= n; ++k) {
for (int i = 1; i <= n; ++i) {
for (int j = 1; j <= n; ++j) {
dis[i][j] = min (dis[i][j], dis[i][k] + dis[k][j]);
}
}
}
for (int i = 1; i <= n; ++i) {
for (int j = 1; j <= n; ++j) {
if (i == j) continue;
for (int k = 1; k <= d; ++k) {
// k-th item-y i-njiden satyn alyan j-nynjyda satyan
if (sell[j][k] != -1 and buy[i][k] != -1) profit[i][j] = max (profit[i][j], sell[j][k] - 0LL - buy[i][k]);
}
}
}
// cout << check(2);
// return 0;
ll l = 1, r = INF, jog = 0;
while (l <= r) {
int md = (l + r) / 2;
if (check (md)) {
jog = md;
l = md + 1;
}
else {
r = md - 1;
}
}
cout << jog;
}
