#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 110;
const int K = 1100;
const int INF = (int)(2e18);
int n, m, k, b[N][K], s[N][K], p[N][N], d[N][N];
vector<array<int, 3>> edge;
bool solve(int t) {
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++)
d[i][j] = INF;
for (auto [u, v, w] : edge)
d[u][v] = min(d[u][v], w * t);
for (int k = 1; k <= n; k++)
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++)
if (d[i][k] < INF && d[k][j] < INF)
d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++)
if (d[i][j] < INF)
d[i][j] -= p[i][j];
for (int k = 1; k <= n; k++)
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++)
if (d[i][k] < INF && d[k][j] < INF)
d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
for (int i = 1; i <= n; i++)
if (d[i][i] <= 0)
return true;
return false;
}
int32_t main() {
ios::sync_with_stdio(0); cin.tie(0);
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, w; cin >> u >> v >> w;
edge.push_back({u, v, w});
}
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++) {
p[i][j] = 0;
for (int t = 1; t <= k; t++)
if (s[j][t] != -1 && b[i][t] != -1)
p[i][j] = max(p[i][j], s[j][t] - b[i][t]);
}
int l = 0, r = (int)(1e9);
while (l < r) {
int mid = (l + r) / 2;
if (solve(mid + 1)) l = mid + 1;
else r = mid;
}
cout << l;
}
