#pragma GCC optimize("O3", "unroll-loops") // "Ofast"
#pragma GCC target("avx2", "bmi", "bmi2", "lzcnt", "popcnt")
#include <bits/stdc++.h>
//#define int long long
#define vt vector
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
#define ff first
#define ss second
#define dbg(x) cerr << #x << " = " << x << '\n'
#define bit(x, i) ((x) >> (i) & 1)
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vvt = vt< vt<int> >;
const int N = 1e6 + 5, mod = 1e9 + 7, B = 500;
const ll inf = 1e18 + 7, LIM = (1ll << 60);
const double eps = 1e-6;
int n, m, k;
ll b[105][1005], s[105][1005];
vt<pii> g[N], g1[N];
void calc (vt<ll> &d, bool c) {
set<pair<ll, int>> st;
d[1] = 0;
st.insert({0, 1});
while (!st.empty()) {
pii nw = *st.begin();
st.erase(st.begin());
int v = nw.ss;
for (auto [to, w]: (c ? g[v] : g1[v])) {
if (d[to] > d[v] + w) {
d[to] = d[v] + w;
st.insert({d[to], to});
}
}
}
}
void solve () {
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 <= m; i++) {
int x, y, w;
cin >> x >> y >> w;
g[x].pb({y, w});
g1[y].pb({x, w});
}
vt<ll> d(n + 1, inf), d1(n + 1, inf);
calc(d, 0);
calc(d1, 1);
for (int i = 1; i <= n; i++) d[i] += d1[i];
ll ans = 0;
for (int i = 2; i <= n; i++) {
for (int j = 1; j <= k; j++) {
if ((s[i][j] - b[1][j]) > 0) ans = max(ans, (s[i][j] - b[1][j]) / d[i]);
}
}
cout << ans;
cout << '\n';
}
bool testcases = 0;
signed main() {
#ifdef ONLINE_JUDGE
freopen(".in", "r", stdin);
freopen(".out", "w", stdout);
#endif
cin.tie(0) -> sync_with_stdio(0);
int test = 1;
if (testcases) cin >> test;
for (int cs = 1; cs <= test; cs++) {
solve();
}
}
