#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 103;
const int K = 1010;
const ll INF = 1e18;
ll b[N][K], s[N][K];
ll dist[N][N], dis[N][N], diss[N][N];
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
int n, m, k;
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 <= n;i++) {
for (int j = 1;j <= n;j++) {
dist[i][j] = INF;
}
}
for (int i = 1;i <= m;i++) {
int u, v;
ll t;
cin >> u >> v >> t;
dist[u][v] = min(dist[u][v], t);
}
for (int k = 1;k <= n;k++) {
for (int i = 1;i <= n;i++) {
for (int j = 1;j <= n;j++) {
if (dist[i][j] > dist[i][k] + dist[k][j]) {
dist[i][j] = dist[i][k] + dist[k][j];
}
}
}
}
for (int i = 1;i <= n;i++) {
for (int j = 1;j <= n;j++) {
ll mx = -INF;
for (int l = 1;l <= k;l++) {
if (b[i][l] == -1 || s[j][l] == -1) continue;
mx = max(mx, s[j][l] - b[i][l]);
}
diss[i][j] = mx;
}
}
ll l = 0, r = 1e9 + 1;
while (l + 1 < r) {
ll mid = (l + r) / 2;
for (int i = 1;i <= n;i++) {
for (int j = 1;j <= n;j++) {
dis[i][j] = mid * min(INF / mid, dist[i][j]) - diss[i][j];
}
}
for (int k = 1;k <= n;k++) {
for (int i = 1;i <= n;i++) {
for (int j = 1;j <= n;j++) {
if (dis[i][j] > dis[i][k] + dis[k][j]) {
dis[i][j] = dis[i][k] + dis[k][j];
}
}
}
}
bool ch = 0;
for (int i = 1;i <= n;i++) {
if (dis[i][i] <= 0) ch = 1;
}
if (ch) l = mid;
else r = mid - 1;
}
cout << l << '\n';
return 0;
}
/*
4 5 2
10 9 5 2
6 4 20 15
9 7 10 9
-1 -1 16 11
1 2 3
2 3 3
1 4 1
4 3 1
3 1 1
*/
