#include <bits/stdc++.h>
#define ll long long
#define ll1 long long
#define ull unsigned long long
#define dou long double
#define str string
#define vll vector<ll>
#define vi vector<int>
#define pll pair<ll, ll>
#define vpll vector<pll>
#define vbool vector<bool>
#define vstr vector<str>
#define vvll vector<vll>
#define pb push_back
#define pf push_front
#define endl "\n"
#define fr first
#define se second
// #define sortcmp(a) sort(a.begin(), a.end(), cmp)
#define sort(a) sort(a.begin(), a.end())
#define reverse(a) reverse(a.begin(), a.end())
#define speed ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define ordered_set tree<ll, null_type, less_equal<ll>, rb_tree_tag, tree_order_statistics_node_update>
using namespace std;
//using namespace __gnu_pbds;
const ll INF = 1e18;
const int lg = 20;
mt19937 rng(time(0));
ll randll(ll l, ll r){
return uniform_int_distribution<ll>(l, r)(rng);
}
vector<vpll> b;
vvll g;
int main(){
speed;
ll n, m, k;
cin >> n >> m >> k;
g.resize(n+7, vll(n+7, INF));
b.resize(n+7, vpll(k, {-1, -1}));
for(int i = 1; i <= n; i ++){
//g[i][i] = 0;
for(int j = 0; j < k; j ++){
cin >> b[i][j].fr >> b[i][j].se;
}
}
for(int i = 0; i < m; i ++){
ll a, b, c;
cin >> a >> b >> c;
g[a][b] = c;
}
vvll p(n+7, vll(n+7, 0));
for(int a = 1; a <= n; a ++){
for(int c = 1; c <= n; c ++){
for(int i = 0; i < k; i ++){
if(b[a][i].fr == -1 || b[c][i].se == -1) continue;
//cout << a << ' ' << c << ' ' << i << ' ' << b[a][i].fr << ' ' << b[c][i].se << endl;
p[a][c] = max(p[a][c], b[c][i].se-b[a][i].fr);
}
}
}
ll l = 0, r = 1e9+7;
while(r - l > 1){
ll x = (l+r)/2;
vvll newg(n+7, vll(n+7, INF));
for(int i = 1; i <= n; i ++){
for(int j = 1; j <= n; j ++){
newg[i][j] = min(newg[i][j], x*min(INF/x, g[i][j]) - p[i][j]);
}
}
/*for(int i = 1; i <= n; i ++){
for(int j = 1; j <= n; j ++){
if(p[i][j] == -INF) continue;
cout << i << ' ' << j << ' ' << p[i][j] << endl;
}
cout << endl;
}
for(int i = 1; i <= n; i ++){
for(int j = 1; j <= n; j ++){
cout << newg[i][j] << ' ';
}
cout << endl;
}*/
for(int i = 1; i <= n; i ++){
for(int j = 1; j <= n; j ++){
for(int i1 = 1; i1 <= n; i1 ++){
newg[j][i1] = min(newg[j][i1], newg[j][i]+newg[i][i1]);
}
}
}
bool q = 0;
for(int i = 1; i <= n; i ++){
//cout << newg[i][i] << ' ';
if(newg[i][i] <= 0) q = 1;
}
//cout << endl;
if(q) l = x;
else r = x;
}
cout << l << endl;
}
