#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;
typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;
typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)
#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 100001;
template<int SZ> struct Topo {
int N, in[SZ];
vi res, adj[SZ];
void addEdge(int x, int y) {
adj[x].pb(y), in[y] ++;
}
void sort() {
queue<int> todo;
F0R(i,N) if (in[i] == 0) todo.push(i);
while (sz(todo)) {
int x = todo.front(); todo.pop();
res.pb(x);
for (int i: adj[x]) {
in[i] --;
if (!in[i]) todo.push(i);
}
}
}
};
int N,M,K,B[100][1000],S[100][1000];
int prof[100][100],dist[100][100];
array<ll,100> tmp;
vi adj[100];
bool ok(int mid) {
F0R(i,N) {
adj[i].clear();
tmp[i] = 0;
}
F0R(i,N) {
auto TMP = tmp;
F0R(j,N) F0R(k,N) if (j != k && dist[j][k] != MOD)
TMP[k] = max(TMP[k],tmp[j]+prof[j][k]-(ll)dist[j][k]*mid);
tmp = TMP;
}
Topo<100> T = Topo<100>(); T.N = N;
F0R(j,N) F0R(k,N) if (j != k && dist[j][k] != MOD) {
ll d = tmp[j]+prof[j][k]-(ll)dist[j][k]*mid;
if (tmp[k] < d) return 1;
else if (tmp[k] == d) T.addEdge(j,k);
}
T.sort();
return sz(T.res) != N;
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> N >> M >> K;
F0R(i,N) F0R(j,K) cin >> B[i][j] >> S[i][j];
F0R(i,N) F0R(j,N) if (i != j) dist[i][j] = MOD;
F0R(i,M) {
int V,W,T; cin >> V >> W >> T; V--, W--;
dist[V][W] = min(dist[V][W],T);
}
F0R(k,N) F0R(i,N) F0R(j,N) dist[i][j] = min(dist[i][j],dist[i][k]+dist[k][j]);
F0R(i,N) F0R(j,N) {
F0R(k,K) if (B[i][k] != -1 && S[j][k] != -1)
prof[i][j] = max(prof[i][j],S[j][k]-B[i][k]);
// cout << "AH " << i << " " << j << " " << prof[i][j] << " " << dist[i][j] << "\n";
}
ok(6);
int lo = 0, hi = MOD;
while (lo < hi) {
int mid = (lo+hi+1)/2;
if (ok(mid)) lo = mid;
else hi = mid-1;
}
cout << lo;
}
/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( )
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
*/
