#include <bits/stdc++.h>
using namespace std;
#define task "main"
#define F first
#define S second
#define ii pair<int, int>
#define il pair<int, long long>
#define li pair<long long, int>
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define FOD(i, b, a) for(int i = (b); i >= (a); --i)
template <class T1, class T2>
bool maximize(T1 &a, T2 b){
if (a < b) {a = b; return true;}
return false;
}
template <class T1, class T2>
bool minimize(T1 &a, T2 b){
if (a > b) {a = b; return true;}
return false;
}
template <class T>
void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){
for(auto item: container) out << item << separator;
out << finish;
}
const int MAX_N = 102;
const int MAX_M = 9902;
const int MAX_K = 1002;
int nNode, nEdge, nItem;
vector<ii> adj[MAX_N];
int buy[MAX_K][MAX_N], sell[MAX_K][MAX_N];
int maxProfit[MAX_N][MAX_N]; // maxProfit[i][j]: maximum profit when buy an item at market i and sell it at market j
long long initDist[MAX_N][MAX_N], curDist[MAX_N][MAX_N];
void floyd(long long dist[MAX_N][MAX_N]) {
FOR(k, 1, nNode) FOR(u, 1, nNode) FOR(v, 1, nNode) {
minimize(dist[u][v], dist[u][k] + dist[k][v]);
}
}
void findMaxProfit() {
memset(maxProfit, 0, sizeof(maxProfit));
FOR(i, 1, nNode) FOR(j, 1, nNode) if (i != j) FOR(item, 1, nItem)
if (buy[item][i] != -1 && sell[item][j] != -1)
maximize(maxProfit[i][j], -buy[item][i] + sell[item][j]);
}
bool valid(long long val) {
memset(curDist, 0x3f, sizeof(curDist));
FOR(u, 1, nNode) FOR(v, 1, nNode) curDist[u][v] = initDist[u][v] * val - maxProfit[u][v];
floyd(curDist);
FOR(u, 1, nNode) if (curDist[u][u] <= 0) return true;
return false;
}
void solve() {
cin >> nNode >> nEdge >> nItem;
FOR(i, 1, nNode) FOR(j, 1, nItem)
cin >> buy[j][i] >> sell[j][i];
memset(initDist, 0x3f, sizeof(initDist));
FOR(i, 1, nEdge) {
int u, v, w;
cin >> u >> v >> w;
initDist[u][v] = w;
}
floyd(initDist);
findMaxProfit();
long long l = 0, r = (long long)1e9, res = 0;
while (l <= r) {
long long mid = (l + r) >> 1;
if (valid(mid)) l = (res = mid) + 1;
else r = mid - 1;
}
cout << res << "\n";
}
int32_t main() {
if (fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
bool multitest = 0;
int numTest = 1;
if (multitest) cin >> numTest;
while (numTest--) {
solve();
}
return 0;
}
/* Lak lu theo dieu nhac!!!! */
