/* be name khoda */
#define long_enable
#include <iostream>
#include <algorithm>
#include <cstring>
#include <numeric>
#include <vector>
#include <fstream>
#include <set>
#include <map>
using namespace std;
#ifdef long_enable
typedef long long int ll;
#else
typedef int ll;
#endif
typedef pair<ll, ll> pii;
typedef pair<pii, ll> ppi;
typedef pair<ll, pii> pip;
typedef vector<ll> vi;
typedef vector<pii> vpii;
#define forifrom(i, s, n) for (ll i = s; i < n; ++i)
#define forirto(i, n, e) for (ll i = (n) - 1; i >= e; --i)
#define fori(i, n) forifrom (i, 0, n)
#define forir(i, n) forirto (i, n, 0)
#define F first
#define S second
#define pb push_back
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define smin(a, b) a = min(a, (b))
#define smax(a, b) a = max(a, (b))
#define debug(x) cout << #x << " -> " << (x) << endl
#define debug2(x, y) cout << #x << ' ' << #y << " -> " << (x) << ' ' << (y) << endl
#define debug3(x, y, z) cout << #x << ' ' << #y << ' ' << #z << " -> " << (x) << ' ' << (y) << ' ' << (z) << endl
#define debug4(x, y, z, t) cout << #x << ' ' << #y << ' ' << #z << ' ' << #t << " -> " << (x) << ' ' << (y) << ' ' << (z) << ' ' << (t) << endl
#define debugp(x) cout << #x << " -> " << "(" << (x).F << ", " << (x).S << ")" << endl
#define debuga(x, n) cout << #x << " -> "; fori (i1_da, n) { cout << (x)[i1_da] << ' '; } cout << endl
#define debugap(x, n) cout << #x << " ->\n"; fori (i1_dap, n) { cout << "(" << (x)[i1_dap].F << ", " << (x)[i1_dap].S << ")\n"; } cout << endl
#define debugaa(x, n, m) cout << #x << " ->\n"; fori (i1_daa, n) { fori (i2_daa, m) { cout << (x)[i1_daa][i2_daa] << ' '; } cout << '\n'; } cout << endl
#define debugav(x, n) cout << #x << " ->\n"; fori (i1_dav, n) { fori (i2_dav, (x)[i1_dav].size()) { cout << (x)[i1_dav][i2_dav] << ' '; } cout << '\n'; } cout << endl
#define debugia(x, n) cout << #x << " ->\n"; fori (i1_dia, n) { cout << i1_dia << " : " << (x)[i1_dia] << '\n'; } cout << endl
const ll MOD = 1000000007;
const ll INF = 2000000000;
const long long BIG = 1446803456761533460LL;
#define Add(a, b) a = ((a) + (b)) % MOD
#define Mul(a, b) a = (1LL * (a) * (b)) % MOD
// -----------------------------------------------------------------------
const ll maxn = 110;
const ll maxk = 1010;
ll n, m, k;
ll S[maxn][maxk], B[maxn][maxk];
ll dis[maxn][maxn], scr[maxn][maxn], d2[maxn][maxn];
bool check(ll p) {
fori (i, n) {
fori (j, n) {
d2[i][j] = dis[i][j] * p - scr[i][j];
}
}
fori (t, n) {
fori (i, n) {
fori (j, n) {
smin(d2[i][j], d2[i][t] + d2[t][j]);
}
}
}
fori (i, n) {
fori (j, i) {
if (d2[i][j] + d2[j][i] <= 0) return true;
}
}
return false;
}
int main() {
ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
// ifstream cin("merchant.in");
cin >> n >> m >> k;
fori (i, n) {
fori (j, k) cin >> B[i][j] >> S[i][j];
}
memset(dis, 20, sizeof dis);
fori (i, n) dis[i][i] = 0;
fori (i, m) {
ll a, b, c; cin >> a >> b >> c; --a, --b;
dis[a][b] = c;
}
fori (t, n) {
fori (i, n) {
fori (j, n) {
smin(dis[i][j], dis[i][t] + dis[t][j]);
}
}
}
fori (i, n) {
fori (j, n) {
fori (t, k) if (B[i][t] != -1 && S[j][t] != -1) smax(scr[i][j], S[j][t] - B[i][t]);
}
}
ll l = 0, r = INF;
while (r - l > 1) {
ll mid = (l + r) / 2;
if (check(mid)) l = mid;
else r = mid;
}
cout << l << '\n';
}
