#include <bits/stdc++.h>
using namespace std;
typedef long double ld;
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<pair<int,int>> vpi;
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)
#define pb push_back
#define rsz resize
#define sz(x) int(x.size())
#define all(x) begin(x), end(x)
#define fi first
#define se second
int const N=1e2+3;
int const K=1e3+3;
ll b[N][K],s[N][K];
vpi adj[N];
vpi rev[N];
vector<vi>ssc;
int n,m,k;
int state[N];
stack<int>kossta;
int sscid[N];
ll d[N];
ll drev[N];
void kosdfs(int u)
{
if(state[u]!=0)return;
state[u]=1;
trav(e,adj[u])
{
kosdfs(e.fi);
}
state[u]=2;
kossta.push(u);
return;
}
void kosdfs2(int u)
{
if(state[u]!=0)return;
ssc.back().pb(u);
sscid[u]=sz(ssc)-1;
state[u]=1;
trav(e,rev[u])
{
kosdfs2(e.fi);
}
kossta.push(u);
return;
}
void kos()
{
fill(state,state+n,0);
F0R(i,n)kosdfs(i);
fill(state,state+n,0);
while(!kossta.empty())
{
int u=kossta.top();
kossta.pop();
if(state[u]!=0)continue;
ssc.pb({});
kosdfs2(u);
}
}
void dij(int src)
{
fill(d,d+n,2e9);
priority_queue<pii>pq;
fill(state,state+n,0);
pq.push({0,src});
while(!pq.empty())
{
int u,w;
tie(w,u)=pq.top();
pq.pop();
if(state[u]==1)continue;
state[u]=1;
trav(e,adj[u])
{
int cand = -w+e.se;
if(cand<d[e.fi])
{
pq.push({-cand,e.fi});
d[e.fi]=cand;
}
}
}
}
void dijrev(int src)
{
fill(drev,drev+n,2e9);
priority_queue<pii>pq;
fill(state,state+n,0);
pq.push({0,src});
while(!pq.empty())
{
int u,w;
tie(w,u)=pq.top();
pq.pop();
if(state[u]==1)continue;
state[u]=1;
trav(e,rev[u])
{
int cand = -w+e.se;
if(cand<drev[e.fi])
{
pq.push({-cand,e.fi});
drev[e.fi]=cand;
}
}
}
}
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,m)
{
int a,u,t;
cin>>a>>u>>t;
--a;--u;
adj[a].pb({u,t});
rev[u].pb({a,t});
}
//kos();
dij(0);
dijrev(0);
ll mx=0;
FOR(i,1,n)
{
F0R(j,k)
{
if(s[i][j]==-1||b[0][j]==-1)continue;
mx=max(mx,(s[i][j]-b[0][j])/(d[i]+drev[i]));
}
}
cout<<mx<<'\n';
return 0;
}
