#include <bits/stdc++.h>
#define nl "\n"
#define no "NO"
#define yes "YES"
#define fi first
#define se second
#define vec vector
#define task "main"
#define _mp make_pair
#define ii pair<int, int>
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define evoid(val) return void(std::cout << val)
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define FOD(i, b, a) for(int i = (b); i >= (a); --i)
#define unq(x) sort(all(x)); x.resize(unique(all(x)) - x.begin())
using namespace std;
template<typename U, typename V> bool maxi(U &a, V b) {
if (a < b) { a = b; return 1; } return 0;
}
template<typename U, typename V> bool mini(U &a, V b) {
if (a > b or a == -1) { a = b; return 1; } return 0;
}
const int mod = (int)1e9 + 7;
void prepare(); void main_code();
int main() {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
if (fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
const bool MULTITEST = 0; prepare();
int num_test = 1; if (MULTITEST) cin >> num_test;
while (num_test--) { main_code(); }
}
void prepare() {};
const int N = (int)107;
const int K = (int)1007;
int n, m, k;
int buy[N][K], sell[N][K];
long long d[N][N];
int prof[N][N];
long long dp[N];
const long long INF = -(long long)1e15;
long long d2[N][N];
bool check(int x) {
FOR(i, 1, n) FOR(j, 1, n) {
if (i == j or d[i][j] == -1)
d2[i][j] = INF;
else {
d2[i][j] = 1LL * prof[i][j] - 1LL * d[i][j] * x;
}
}
FOR(i, 1, n) {
FOR(j, 1, n) if (j != i and d[i][j] != -1 and d[j][i] != -1) {
maxi(d2[i][i], 1LL * prof[i][i] - (d[i][j] + d[j][i]) * x);
}
}
FOR(k, 1, n)
FOR(i, 1, n)
FOR(j, 1, n) {
maxi(d2[i][j], d2[i][k] + d2[k][j]);
}
FOR(i, 1, n) if (d2[i][i] >= 0)
return 1;
return 0;
}
void main_code() {
int K;
cin >> n >> m >> K;
FOR(i, 1, n) {
FOR(j, 1, K) {
cin >> buy[i][j] >> sell[i][j];
}
}
memset(d, -1, sizeof d);
FOR(i, 1, n) d[i][i] = 0;
for(int i = 1; i <= m; ++i) {
int u, v, w;
cin >> u >> v >> w;
d[u][v] = w;
}
FOR(k, 1, n)
FOR(i, 1, n) if (d[i][k] != -1)
FOR(j, 1, n) if (d[k][j] != -1) {
mini(d[i][j], d[i][k] + d[k][j]);
}
FOR(i, 1, n) FOR(j, 1, n) if (d[i][j] != -1) {
FOR(k, 1, K) if (sell[j][k] != -1 and buy[i][k] != -1)
prof[i][j] = max(prof[i][j],
sell[j][k] - buy[i][k]);
}
int lb = 1, rb = (int)1e9, ans = 0;
while (lb <= rb) {
int mid = (lb + rb) >> 1;
if (check(mid)) {
ans = mid;
lb = mid + 1;
} else {
rb = mid - 1;
}
}
cout << ans;
}
/* Let the river flows naturally */
