/* made by amunduzbaev */
#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
//using namespace __gnu_pbds;
#define ff first
#define vv vector
#define ss second
#define pb push_back
#define mp make_pair
#define ub upper_bound
#define lb lower_bound
#define sz(x) (int)x.size()
#define tut(x) array<int, x>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(),x.rend()
#define NeedForSpeed ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define int long long
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef vector<int> vii;
typedef vector<pii> vpii;
template<class T> bool umin(T& a, const T& b) { return a > b? a = b, true:false; }
template<class T> bool umax(T& a, const T& b) { return a < b? a = b, true:false; }
//void usaco(string s) { freopen((s+".in").c_str(),"r",stdin);
//freopen((s+".out").c_str(),"w",stdout); }
//template<class T> tree<T,
//less<T>, null_type, rb_tree_tag,
//tree_order_statistics_node_update> ordered_set;
const int N = 105;
const int mod = 1e9+7;
const ll inf = 1e17;
const ld Pi = acos(-1);
const int B = 1e7;
#define MULTI 0
int n, m, k, ans, q, res, a[N];
int b[N][1005], s[N][1005];
int tt[N][N], mx[N][N], is[N][N], prof[N][N];
pii cd[N][N];
void solve(int t_case){
cin>>n>>m>>k;
for(int i=1;i<=n;i++){
for(int j=0;j<k;j++){
cin>>b[i][j]>>s[i][j];
}
}
for(int i=1;i<=n;i++) for(int j=1;j<=n;j++) tt[i][j] = inf;
for(int i=0;i<m;i++){
int a, b, c; cin>>a>>b>>c;
umin(tt[a][b], c);
}
for(int k=1;k<=n;k++){
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
umin(tt[i][j], tt[i][k] + tt[k][j]);
}
}
} int K = k;
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
for(int k=0;k<K;k++){
if(~b[i][k] && ~s[j][k])
umax(prof[i][j], - b[i][k] + s[j][k]);
} cd[i][j] = {prof[i][j], tt[i][j]};
mx[i][j] = prof[i][j] * B / tt[i][j];
}
}
for(int i=1;i<=n;i++){
priority_queue<tut(4)> qq;
for(int j=1;j<=n;j++) if(tt[i][j] < inf) qq.push({mx[i][j], prof[i][j], tt[i][j], j});
while(!qq.empty()){
tut(4) x = qq.top(); qq.pop();
if(x[0] < mx[i][x[3]]) continue;
for(int j=1;j<=n;j++){
if(tt[i][j] == inf) continue;
int cost = x[1] + prof[x[3]][j], dis = x[2] + tt[x[3]][j];
if(umax(mx[i][j], cost * B / dis)) cd[i][j] = {cost, dis}, qq.push({mx[i][j], cost, dis, j});
}
}
}
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++) umax(res, (cd[i][j].ff + cd[j][i].ff) / (cd[i][j].ss + cd[j][i].ss));
cout<<res<<"\n";
}
signed main(){
NeedForSpeed
if(!MULTI) {
solve(1);
} else {
int t; cin>>t;
for(int t_case = 1; t_case <= t; t_case++) solve(t_case);
} return 0;
}
