#include <bits/stdc++.h>
using namespace std;
void just_do_it();
int main() {
#ifdef KAMIRULEZ
freopen("kamirulez.inp", "r", stdin);
freopen("kamirulez.out", "w", stdout);
#endif
ios_base::sync_with_stdio(0);
cin.tie(0);
just_do_it();
return 0;
}
const int maxN = 1e2 + 20;
const int maxK = 1e3 + 20;
const int inf1 = 1e9 + 20;
const long long inf2 = 1e18L + 20;
int buy[maxN][maxK];
int sell[maxN][maxK];
int dist[maxN][maxN];
int prof[maxN][maxN];
long long cost[maxN][maxN];
long long dist2[maxN];
bool flag[maxN];
int N, M, K;
bool dfs(int u) {
flag[u] = true;
for (int v = 1; v <= N; v++) {
if (v != u && dist2[u] + cost[u][v] == dist2[v]) {
if (flag[v] || dfs(v)) {
return true;
}
}
}
return false;
}
bool check() {
for (int i = 1; i <= N; i++) {
dist2[i] = 0;
}
for (int iter = 0; iter < N; iter++) {
for (int i = 1; i <= N; i++) {
for (int j = 1; j <= N; j++) {
if (dist2[j] < dist2[i] + cost[i][j]) {
if (iter == N - 1) {
return true;
}
dist2[j] = dist2[i] + cost[i][j];
}
}
}
}
for (int i = 1; i <= N; i++) {
flag[i] = false;
}
for (int i = 1; i <= N; i++) {
if (!flag[i] && dfs(i)) {
return true;
}
}
return false;
}
void just_do_it() {
cin >> N >> M >> K;
for (int i = 1; i <= N; i++) {
for (int j = 1; j <= N; j++) {
if (i == j) {
dist[i][j] = 0;
}
else {
dist[i][j] = inf1;
}
}
}
for (int i = 1; i <= N; i++) {
for (int j = 1; j <= K; j++) {
cin >> buy[i][j] >> sell[i][j];
}
}
for (int i = 1; i <= M; i++) {
int u, v, w;
cin >> u >> v >> w;
dist[u][v] = min(dist[u][v], w);
}
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]);
}
}
}
for (int i = 1; i <= N; i++) {
for (int j = 1; j <= N; j++) {
prof[i][j] = 0;
for (int k = 1; k <= K; k++) {
if (buy[i][k] != -1 && sell[j][k] != -1) {
prof[i][j] = max(prof[i][j], sell[j][k] - buy[i][k]);
}
}
}
}
int res = 0;
int lt = 1;
int rt = inf1;
while (lt <= rt) {
int mt = (lt + rt) / 2;
for (int i = 1; i <= N; i++) {
for (int j = 1; j <= N; j++) {
if (dist[i][j] == inf1) {
cost[i][j] = -inf2;
}
else {
cost[i][j] = 1LL * prof[i][j] - 1LL * dist[i][j] * mt;
}
}
}
if (check()) {
res = mt;
lt = mt + 1;
}
else {
rt = mt - 1;
}
}
cout << res;
}
