#include <bits/stdc++.h>
// #define int int64_t //be careful about this
using namespace std;
#define vt vector
#define ar array
#define pr pair
#define f first
#define s second
#define pb push_back
#define eb emplace_back
#define fr(i,a,b) for(int i = (a); i < (b); ++i)
#define rf(i,a,b) for(int i = (b)-1; i >= (a); --i)
#define all(x) x.begin(),x.end()
#define mem(a,b) memset(a,b,sizeof(a))
namespace IN{
template<class T> void re(vector<T> &A);
template<class S,class T> void re(pair<S,T> &A);
template<class T,size_t N> void re(array<T,N> &A);
template<class T> void re(T& x){
cin >> x;}
template<class H, class... T> void re(H& h, T&... t){
re(h); re(t...);}
template<class T> void re(vector<T> &A){
for(auto& x : A) re(x);}
template<class S,class T> void re(pair<S,T> &A){
re(A.first); re(A.second);}
template<class T,size_t N> void re(array<T,N> &A){
for(int i = 0; i < N; ++i) re(A[i]);}
}
namespace OUT{
template<class T>
void __p(const T& a){ cout<<a; }
template<class T, class F>
void __p(const pair<T, F>& a){ cout<<"{"; __p(a.first); cout<<","; __p(a.second); cout<<"}\n"; }
template<class T, size_t N>
void __p(const array<T,N>& a){ cout<<"{"; for(int i=0;i<N;++i)__p(a[i]),cout<<",}\n"[i+1==N]; }
template<class T>
void __p(const vector<T>& a){
cout<<"{";for(auto it=a.begin();it<a.end();it++)__p(*it),cout<<",}\n"[it+1==a.end()]; }
template<class T, class ...Arg>
void __p(T a1, Arg ...a){__p(a1); __p(a...); }
template<class Arg1>
void __f(const char *s, Arg1 &&arg1){ cout<<s<<" : "; __p(arg1); cout<<endl; }
template<class Arg1, class ... Args>
void __f(const char *ss, Arg1 &&arg1, Args &&... args){
int b=0,i=0; do{ if(ss[i]=='(') b++; if(ss[i]==')') b--; i++;}while(!(ss[i]==','&&b==0));
const char *comma=ss+i; cout.write(ss,comma-ss)<<" : ";__p(arg1);cout<<" | ";__f(comma+1,args...);}
#define trace(...) cout<<"Line:"<<__LINE__<<" ", __f(#__VA_ARGS__, __VA_ARGS__)
}
namespace FUNC{
void IO(string s = ""){
ios_base::sync_with_stdio(NULL);
cin.tie(nullptr);
cout.precision(20);
cout << fixed;
if(!s.empty()){
freopen((s+".in").c_str(),"r",stdin);
freopen((s+".out").c_str(),"w",stdout);
}
}
const auto start_time = chrono::high_resolution_clock::now();
void output_run_time(){
// will work for ac,cc&&cf.
#ifndef ONLINE_JUDGE
auto end_time = chrono::high_resolution_clock::now();
chrono::duration<double> diff = end_time-start_time;
cout << "\n\n\nTime Taken : " << diff.count();
#endif
}
template<class T> bool ckmin(T& a, const T& b){
return b < a ? a = b, true : false; }
template<class T> bool ckmax(T& a, const T& b){
return a < b ? a = b, true : false; }
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
int my_rand(int L, int R){
return uniform_int_distribution<int>(L,R)(rng); }
template<class T> int sz(const T& x){
return int(x.size()); }
template<class T> int lb(const vector<T>& vec,const T& val){
return int(lower_bound(vec.begin(), vec.end(),val) - vec.begin()); }
template<class T> int ub(const vector<T>& vec,const T& val){
return int(upper_bound(vec.begin(), vec.end(),val) - vec.begin()); }
constexpr int dx[4] = {1,0,-1,0};
constexpr int dy[4] = {0,1,0,-1};
constexpr char dr[4] = {'D','R','U','L'};
constexpr long long INFLL1 = 1e16, INFLL2 = 9e18;
constexpr int INF = 1e9;
template<class T>
vector<T> V(int n,T val){
return vector<T> (n,val);
}
template<class T>
vector<vector<T>> V(int n,int m,T val){
return vector<vector<T>> (n,vector<T> (m,val));
}
template<class T>
vector<vector<vector<T>>> V(int n,int m,int k,T val){
return vector<vector<vector<T>>> (n,vector<vector<T>> (m,vector<T> (k,val)));
}
}
using namespace IN;
using namespace OUT;
using namespace FUNC;
signed main(){
IO();
int n,m,K;
re(n,m,K);
vt<vt<int>> buy(n,vt<int>(K+1)),sell(n,vt<int>(K+1));
fr(i,0,n){
fr(j,0,K){
re(buy[i][j],sell[i][j]);
}
buy[i][K] = sell[i][K] = 0;
}
vt<vt<int>> dis(n,vt<int>(n,INF));
fr(e,0,m){
int u,v,w; re(u,v,w);
--u,--v;
dis[u][v] = w;
}
fr(k,0,n) fr(i,0,n) fr(j,0,n) ckmin(dis[i][j],dis[i][k]+dis[k][j]);
auto can = [&](int ef) -> bool {
auto min_dis = V<long long>(n,n,INFLL1);
fr(i,0,n){
fr(j,0,n){
if(dis[i][j] == INF) continue;
long long best = -INF;
fr(k,0,K+1){
if(sell[j][k] < 0 || buy[i][k] < 0) continue;
ckmax(best,sell[j][k] - buy[i][k] - ef * 1LL * dis[i][j]);
}
if(best == -INF) continue;
ckmin(min_dis[i][j],-best);
}
}
fr(k,0,n) fr(i,0,n) fr(j,0,n) ckmin(min_dis[i][j],min_dis[i][k]+min_dis[k][j]);
fr(i,0,n) if(min_dis[i][i] <= 0) return true;
return false;
};
int lo = 0, hi = INF;
while(hi - lo > 1){
int mid = (hi + lo)/2;
can(mid) ? lo = mid : hi = mid;
}
cout << lo;
// output_run_time();
return 0;
}
