// EXPLOSION!
#define _CRT_SECURE_NO_WARNINGS
#include<bits/stdc++.h>
#include<unordered_set>
#include<unordered_map>
#include<chrono>
using namespace std;
typedef pair<int, int> pii;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pair<int, int>> vpi;
typedef vector<pair<ll, ll>> vpll;
#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 mp make_pair
#define rsz resize
#define sz(x) int(x.size())
#define all(x) x.begin(),x.end()
#define f first
#define s second
#define cont continue
#define endl '\n'
//#define ednl '\n'
#define test int testc;cin>>testc;while(testc--)
#define pr(a, b) trav(x,a)cerr << x << b; cerr << endl;
#define message cout << "Hello World" << endl;
const int dx[4] = { 1,0,-1,0 }, dy[4] = { 0,1,0,-1 }; // for every grid problem!!
const ll linf = 4000000000000000000LL;
const ll inf = 1000000007;//998244353
void pv(vi a) { trav(x, a)cout << x << " "; cout << endl; }void pv(vll a) { trav(x, a)cout << x << " "; cout << endl; }void pv(vector<vi>a) {
F0R(i, sz(a)) { cout << i << endl; pv(a[i]); cout << endl; }
}void pv(vector<vll>a) { F0R(i, sz(a)) { cout << i << endl; pv(a[i]); }cout << endl; }void pv(vector<string>a) { trav(x, a)cout << x << endl; cout << endl; }
void setIO(string s) {
ios_base::sync_with_stdio(0); cin.tie(0);
#ifdef arwaeystoamneg
if (sz(s))
{
freopen((s + ".in").c_str(), "r", stdin);
if (s != "test1")
freopen((s + ".out").c_str(), "w", stdout);
}
#endif
}
const int MAX = 111;
int n, m, k, A[MAX][10 * MAX], B[MAX][10 * MAX];
int dist[MAX][MAX];
ll best[MAX][MAX], dp[MAX][MAX];
bool check(int x)
{
F0R(i, n)
{
F0R(j, n)
{
ll ans = -(ll)x * dist[i][j];
F0R(l, k)
{
if (A[i][l] == -1 || B[j][l] == -1)continue;
ans = max(ans, B[j][l] - A[i][l] - (ll)x * dist[i][j]);
}
best[i][j] = ans;
}
}
F0R(i, n)fill(dp[i], dp[i] + n, linf);
F0R(i, n)F0R(j, n)dp[i][j] = -best[i][j];
F0R(k, n)
{
F0R(i, n)
{
F0R(j, n)
{
if (dp[i][j] > dp[i][k] + dp[k][j])
dp[i][j] = dp[i][k] + dp[k][j];
}
}
}
F0R(i, n)if (dp[i][i] <= 0)return 1;
return 0;
}
int main()
{
setIO("test1");
cin >> n >> m >> k;
F0R(i, n)
{
F0R(j, k)cin >> A[i][j] >> B[i][j];
fill(dist[i], dist[i] + n, inf);
}
F0R(i, m)
{
int x, y, z;
cin >> x >> y >> z;
x--, y--;
dist[x][y] = min(dist[x][y], z);
}
F0R(k, n)
{
F0R(i, n)
{
F0R(j, n)
{
if (dist[i][j] > dist[i][k] + dist[k][j])
{
dist[i][j] = dist[i][k] + dist[k][j];
}
}
}
}
int l = 0, r = inf;
while (l < r)
{
int m = (l + r + 1) / 2;
if (check(m))l = m;
else r = m - 1;
}
cout << l << endl;
}
