#include<bits/stdc++.h>
using namespace std;
const long long inf = (long long) 1e18 + 10;
const int inf1 = (int) 1e9 + 10;
#define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
const int maxn = 110;
const int maxk = 1100;
int n,m,k, b[maxn][maxk], s[maxn][maxk], dfw[maxn][maxn], d[maxn][maxn], g[maxn][maxn], a[maxn][maxn];
void solve() {
cin >> n >> m >> k;
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= k; j++) {
cin >> b[i][j];
if(b[i][j] == -1) b[i][j] = inf;
cin >> s[i][j];
if(s[i][j] == -1) s[i][j] = -inf;
}
}
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= n; j++) {
dfw[i][j] = inf;
}
dfw[i][i] = 0;
}
for(int i = 1; i <= m; i++) {
int u,v,w; cin >> u >> v >> w;
dfw[u][v] = min(dfw[u][v],w);
}
for(int v = 1; v <= n; v++) {
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= n; j++) {
dfw[i][j] = min(dfw[i][j], dfw[i][v]+dfw[v][j]);
}
}
}
for(int u = 1; u <= n; u++) {
for(int v = 1; v <= n; v++) {
a[u][v] = -inf;
//compra em u e vende em v
for(int i = 1; i <= n; i++) {
a[u][v] = max(a[u][v],s[v][i]-b[u][i]);
}
}
}
int l = 1;
int r = inf1*2*n; //valor maximo fodase
int ans = 0;
while(l <= r) {
int mid = (l+r)>>1;
//cria as arestas
for(int u = 1; u <= n; u++) {
for(int v = 1; v <= n; v++) {
g[u][v] = a[u][v]-dfw[u][v]*mid;
// cout << u << " " << v << " " << g[u][v] << endl;
}
}
//encontrar se tem ciclo positivo em um grafo bellman fodase
bool ok = false;
for(int beg = 1; beg <= n; beg++) {
for(int i = 1; i <= n; i++) {
d[i][0] = -inf;
}
d[beg][0] = 0;
for(int i = 1; i <= n+1; i++) {
for(int u = 1; u <= n; u++) d[u][i] = -inf;
for(int u = 1; u <= n; u++) {
for(int v = 1; v <= n; v++) {
if(u == v) continue;
d[v][i] = max(d[v][i],d[u][i-1] + g[u][v]);
}
}
}
for(int i = 1; i <= n+1; i++) {
if(d[beg][i] >= 0) ok = true;
// cout << beg << " = " << i << " " << d[i][n+1] << endl;
}
}
if(ok) {
ans = mid;
l = mid+1;
}
else {
r = mid-1;
}
}
cout << ans << endl;
}
int32_t main() {
ios::sync_with_stdio(false); cin.tie(0);
// freopen("in.in", "r", stdin);
// freopen("out.out", "w", stdout);
int tt = 1;
// cin >> tt;
while(tt--) solve();
}
