#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, m, k; cin >> n >> m >> k;
vector<vector<pair<int, int>>> trade(n+1, vector<pair<int, int>>(k));
for(int i = 1; i <= n; i++){
for(int y = 0; y < k; y++){
cin >> trade[i][y].first >> trade[i][y].second;
}
}
//f = buy, s = sell
vector<vector<int>> g(n+1, vector<int>(n+1, 1e18));
for(int y = 0; y < m; y++){
int u, v, p; cin >> u >> v >> p;
g[u][v] = p;
}
for(int i = 1; i <= n; i++){
g[i][i] = 0;
}
for(int y = 1; y <= n; y++){
for(int i = 1; i <= n; i++){
for(int z = 1; z <= n; z++){
g[i][z] = min(g[i][z], g[i][y] + g[y][z]);
}
}
}
vector<vector<int>> mx(n+1, vector<int>(n+1, 0LL));
for(int i = 1; i <= n; i++){
for(int y = 1; y <= n; y++){
for(int z = 0; z < k; z++){
if(trade[y][z].second == -1 || trade[i][z].first == -1) continue;
mx[i][y] = max(mx[i][y], trade[y][z].second - trade[i][z].first);
}
}
}
int ns = 0;
for(int i = 1; i <= n; i++){
vector<pair<int, int>> dp(n+1, {-1e18, 1});
dp[i] = {0, 0};
for(int aw = 0; aw < n; aw++){
for(int y = 1; y <= n; y++){
for(int z = 1; z <= n; z++){
if(y == z || dp[y].first == -1e18) continue;
auto [c, v] = dp[y];
c += mx[y][z];
v += g[y][z];
//c/v > dp[z].first/dp[z].second
long double per = c;
per *= dp[z].second;
long double per2 = dp[z].first;
per2 *= v;
if(per >= per2 && c/v >= 0){
dp[z] = {c, v};
}
}
}
}
// cout << i << " " << dp[i].first << " " << dp[i].second << "\n";;
if(dp[i] == make_pair(0LL, 0LL)) continue;
int j = (dp[i].first/dp[i].second);
ns = max(ns, j);
}
cout << ns << "\n";
return 0;
}
