//```// YF YUSUF
#include <bits/stdc++.h>
// #include <iostream>
// #include <vector>
// #include <set>
// #include <map>
// #include <algorithm>
// #include <cmath>
// #include <numeric>
// #include <queue>
// #include <stack>
// #include <cassert>
// #include <climits>
// #include <string>
// #include <cstdlib>
// #include <random>
// #include <iomanip>
// #include <ctime>
using namespace std;
#ifdef YF_CHECK
bool LOCAL = 1;
#else
#pragma GCC optimize ("unroll-loops")
#pragma GCC optimize ("inline")
#pragma GCC optimize ("Ofast")
#pragma GCC optimize ("O3")
bool LOCAL = 0;
#endif
using ll = long long;
using ld = long double;
using vll = vector <ll>;
using mll = map <ll,ll>;
using pll = pair <ll,ll>;
using vvl = vector <vll>;
using vpll = vector <pll>;
template<class T>T MIN(T&a,T b){a=min(a,b);return a;}
template<class T>T MAX(T&a,T b){a=max(a,b);return a;}
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define sgr v+v+1,(tl+tr)/2+1,tr
#define sgl v+v,tl,(tl+tr)/2
#define pb push_back
#define ins insert
#define S second
#define F first
mt19937_64 MT(time(0));
ll BP(ll a,ll b,ll mod=1e9+7){
if(b==0)return 1;
ll q=BP(a,b/2,mod);
return ((q*q)%mod*(b%2?a:1ll))%mod;
}
ll f(ll x){return x*(x+1)/2;}
ll dup(ll a,ll b){return (a+b-1)/b;}
ll lcm(ll a,ll b){return a/__gcd(a,b)*b;}
ll invf(ll x){return (-1+sqrt(1+8*x))/2;}
ll lg(ll x){return (x ? 63 - __builtin_clzll(x) : -1);}
const ll mod=998244353;
const ll INF=1e18;
const ll inf=1e9+7;
const ll N =1e2+7;
const ll K =1e3+7;
ll n, m, k, ns, d[N][N], c[N][N];
vpll g[N];
ll b[N][K], s[N][K];
pll DH(ll x){return {x / ns, x % ns};}
ll H(ll nn,ll kk){return (kk * ns + nn);}
void YF_MAIN(ll TEST){
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<=n;i++)
for(int j=1;j<=n;j++)
d[i][j] = INF;
for(int i=1;i<=m;i++){
ll v, u, w;
cin>>v>>u>>w;
MIN(d[v][u], w);
}
for(int k=1;k<=n;k++){
for(int i=1;i<=n;i++){
for(int j=1;j<=n;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++){
for(int q=1;q<=k;q++){
if(s[j][q] == -1 || b[i][q] == -1)continue;
MAX(c[i][j], s[j][q] - b[i][q]);
}
}
}
ll L = 0, R = inf, ans = 0;
while(L <= R){
ll mid = (R + L)>>1;
bool can = 0;
for(int st=1; st<=1; st++){
ll s=1,f=n;
priority_queue <pll> q;
vector<ll> D(n+1,-inf),p(n+1,0);
D[s]=0;
q.push({0,s});
int cnt = 0;
// bool out = (mid == 125000000);
bool out = 0;
while(q.size()){
auto [dist,v] = q.top();
q.pop();
if(out)cout<<dist<<" "<<v<<" : ";
for(int to=1; to<=n; to++)if(to != v && d[v][to] != INF){
ll csto = D[v] + c[v][to] - mid * d[v][to];
if(out)cout<<to<<" "<<csto<<" "<<c[v][to] <<" "<< d[v][to]<<", ";
if(to == st && csto >= 0){
can = 1;
break;
}
if(D[to] < csto){
D[to] = D[v] + c[v][to] - mid * d[v][to];
q.push({D[to], to});
}
}
if(out)cout<<"\n";
}
if(out)cout<<mid<<" mid\n\n";
if(can){
break;
}
}
if(can) {
L = mid + 1;
ans = mid;
} else {
R = mid - 1;
}
}
cout<<ans;
}
const bool TECT=0;
const bool FLSH=1;
const ll SN=1e0 + 7; ll SM[SN];
const ll FN=1e0 + 7; ll FACT[FN], inv[FN], FMOD=inf;
ll PNK(ll n,ll k){return FACT[n] *inv[n-k]%FMOD;}
ll CNK(ll n,ll k){return PNK(n,k)*inv[k ]%FMOD;}
void BEFORE(){
for(ll i=2;i<SN;i++){
if(SM[i])continue;
for(ll j=i;j<SN;j+=i)
MAX(SM[j],i);
}
FACT[0]=inv[0]=1;
for(int i=1;i<FN;i++){
FACT[i]=FACT[i-1]*i%FMOD;
inv[i]=BP(FACT[i],FMOD-2,FMOD);
}
}
signed main(){
// freopen(("input.txt"),"r",stdin);freopen(("output.txt"),"w",stdout);
if(FLSH){
ios_base::sync_with_stdio(0);
cout.setf(ios::fixed);
cout.precision(0);
cout.tie(0);
cin.tie(0);
}
int TEST=1;
if(TECT)
cin>>TEST;
BEFORE();
for(int T=1;T<=TEST;T++){
// cout<<"Case "<<T<<": ";
YF_MAIN(T);
cout<<(T==TEST ? "" : "\n");
}
return 0;
}
// YF YUSUF ```
