#include <bits/stdc++.h>
using namespace std;
#define int long long
const int INF = 0x3f3f3f3f;
bool bellman(int x, const vector<vector<int>> &dist, const vector<vector<int>> &maxDiff, int N)
{
vector<int> d(N+1, 0);
vector<vector<int>> peso(N+1, vector<int>(N+1));
for (int i = 1; i <= N; i++)
for (int j = 1; j <= N; j++)
peso[i][j] = x*dist[i][j] - maxDiff[i][j];
for (int t = 1; t <= N; t++)
for (int i = 1; i <= N; i++)
for (int j = 1; j <= N; j++)
d[j] = min(d[j], d[i] + peso[i][j]);
for (int i = 1; i <= N; i++)
for (int j = 1; j <= N; j++)
if (d[j] > d[i] + peso[i][j]) return true;
return false;
}
int32_t main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int N, M, K;
cin >> N >> M >> K;
vector<vector<pair<int, int>>> items(N+1, vector<pair<int, int>>(K));
for (int i = 1; i <= N; i++)
for (auto &[B,S] : items[i]) {cin >> B >> S;}
vector<vector<int>> maxDiff(N+1, vector<int>(N+1));
for (int i = 1; i <= N; i++)
for (int j = 1; j <= N; j++)
{
if (i == j) continue;
for (int k = 0; k < K; k++)
{
auto [Bi, Si] = items[i][k];
auto [Bj, Sj] = items[j][k];
if (Bi == -1 || Sj == -1) continue;
if (Bi > Sj) continue;
maxDiff[i][j] = max(maxDiff[i][j], Sj - Bi);
}
}
items.clear();
vector<vector<int>> dist(N+1, vector<int>(N+1, INF));
for (int i = 1; i <= M; i++)
{
int X, Y, P;
cin >> X >> Y >> P;
dist[X][Y] = min(dist[X][Y], P);
}
for (int i = 1; i <= N; i++) dist[i][i] = 0;
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]);
int ini = -1, fim = INF;
while (ini < fim)
{
int m = (ini + fim + 1) >> 1;
if (bellman(m, dist, maxDiff, N)) ini = m;
else fim = m-1;
}
cout << ini+1 << '\n';
}
