#include <bits/stdc++.h>
#define maxn 101
#define maxm 9901
#define maxk 1001
#define fi first
#define se second
using namespace std;
typedef pair<int, int> ii;
int n, m, k;
int s[maxn][maxk], b[maxn][maxk];
int c[maxn][maxn];
int64_t kc[maxn][maxn];
int64_t dp[maxn][maxn];
struct edge {
int u, v, l;
edge() {}
edge(int _u, int _v, int _l) : u(_u), v(_v), l(_l) {}
};
edge e[maxm];
bool ok(int x) {
for (int i = 1; i <= n; i++) for (int j = 1; j <= n; j++) kc[i][j] = LLONG_MAX/2;
for (int i = 1; i <= n; i++) kc[i][i] = 0;
for (int i = 1; i <= m; i++) {
int u = e[i].u, v = e[i].v, l = e[i].l;
kc[u][v] = min(kc[u][v], int64_t(l)*x);
}
for (int i = 1; i <= n; i++) kc[i][i] = LLONG_MAX/2;
for (int k = 1; k <= n; k++) {
for (int i = 1; i <= n; i++) for (int j = 1; j <= n; j++) kc[i][j] = min(kc[i][j], kc[i][k] + kc[k][j]);
}
for (int i = 1; i <= n; i++) for (int j = 1; j <= n; j++) {
if (kc[i][j] == LLONG_MAX/2) dp[i][j] = LLONG_MAX/2;
else dp[i][j] = kc[i][j] - c[i][j];
}
for (int k = 1; k <= n; k++) {
for (int i = 1; i <= n; i++) for (int j = 1; j <= n; j++) dp[i][j] = min(dp[i][j], dp[i][k] + dp[k][j]);
}
for (int i = 1; i <= n; i++) if (dp[i][i] <= 0) return true;
return false;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> m >> k;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= k; j++) cin >> b[i][j] >> s[i][j];
}
for (int i = 1; i <= m; i++) {
int u, v, l;
cin >> u >> v >> l;
e[i] = edge(u, v, l);
}
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
if (i == j) continue;
for (int o = 1; o <= k; o++) {
if (b[i][o] == -1 || s[j][o] == -1) continue;
c[i][j] = max(c[i][j], s[j][o] - b[i][o]);
}
}
}
int lo = 0, hi = 1000000001;
while (hi - lo > 1) {
int mid = (lo + hi)>>1;
if (ok(mid)) lo = mid;
else hi = mid;
}
// ok(2);
// ok(3);
// ok(6);
cout << lo;
}
