#include<bits/stdc++.h>
using namespace std;
using ll=long long;
//#pragma GCC optimize("03,unroll-loops")
//#pragma GCC target("avx2")
//#pragma GCC target("sse4")
#define all(v) v.begin(),v.end()
#define F first
#define S second
#define pub push_back
#define pob pop_back
#define puf push_front
#define pof pop_front
//#define randi uniform_int_distribution<long long>
#define damoon(v) v.resize(unique(all(v))-v.begin())
//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
//randi dist(0,10000000000000000);
typedef pair<int,int> pii;
typedef pair<long long,long long> pll;
typedef pair<int,bool> pib;
typedef pair<long long,bool> plb;
typedef pair<int,pii> pip;
typedef pair<pii,int> ppi;
typedef vector<int> veci;
typedef vector<long long> vecl;
typedef vector<bool> vecb;
typedef vector<pii> vecp;
typedef set<int> seti;
typedef set<long long> setl;
typedef set<pii> setp;
typedef map<int,int> mapii;
typedef map<long long,long long> mapll;
typedef map<int,bool> mapib;
typedef map<long long,bool> maplb;
const int mod=1e9+7,neginf=-1e9;
const ll inf=LLONG_MAX/4;
const double PI=acos(-1);
void solve()
{
int n,m,k;
cin>>n>>m>>k;
vector<vecl> b(n,vecl(k));
vector<vecl> s(n,vecl(k));
for(int i=0;i<n;i++)
for(int j=0;j<k;j++)
cin>>b[i][j]>>s[i][j];
vector<vecl> mat(n,vecl(n,inf));
for(int e=0;e<m;e++)
{
int ai,bi;
ll ci;
cin>>ai>>bi>>ci;
ai--;
bi--;
mat[ai][bi]=min(mat[ai][bi],ci);
}
for(int u=0;u<n;u++)
for(int i=0;i<n;i++)
if(mat[i][u]<inf)
for(int j=0;j<n;j++)
if(mat[u][j]<inf)
mat[i][j]=min(mat[i][j],mat[i][u]+mat[u][j]);
vector<vecl> f(n,vecl(n,0));
for(int i=0;i<n;i++)
{
for(int j=0;j<n;j++)
{
ll bst=LLONG_MIN/4;
for(int x=0;x<k;x++)
if(b[i][x]!=-1 and s[j][x]!=-1)
bst=max(bst,s[j][x]-b[i][x]);
f[i][j]=max(bst,0LL);
}
}
ll L=1,R=1000000000LL,ans=0;
vector<vecl> dp(n,vecl(n));
while(L<=R)
{
ll mid=(L+R)>>1;
for(int i=0;i<n;i++)
{
for(int j=0;j<n;j++)
{
if(mat[i][j]>=inf)
{
ll dis=inf/mid;
dp[i][j]=mid*dis-f[i][j];
}
else
{
ll dis=min(mat[i][j],inf/mid);
dp[i][j]=mid*dis-f[i][j];
}
}
}
for(int x=0;x<n;x++)
for(int i=0;i<n;i++)
for(int j=0;j<n;j++)
dp[i][j]=min(dp[i][j],dp[i][x]+dp[x][j]);
bool is=0;
for(int i=0;i<n;i++)
{
if(dp[i][i]<=0)
{
is=1;
break;
}
}
if(is)
{
ans=mid;
L=mid+1;
}
else
{
R=mid-1;
}
}
cout<<ans<<"\n";
}
int main()
{
cin.tie(0);
cout.tie(0);
ios_base::sync_with_stdio(false);
//ifstream fin("in.txt");
//ofstream fout("out.txt");
int t=1;
//cin>>t;
while(t--)
{
solve();
}
}
