#include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>
#include <deque>
#include <map>
#include <set>
#include <complex>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <random>
#define ft first
#define sc second
#define pb push_back
#define len(v) (int)v.size()
#define int ll
#define all(v) v.begin(), v.end()
using namespace std;
typedef long long ll;
typedef long double ld;
int inf = 1e18 + 100;
int infs = 1e9 + 100;
int n, m, k;
vector<vector<int>> cst;
vector<vector<int>> s;
vector<vector<int>> b;
vector<vector<int>> dst;
vector<vector<int>> dst0;
vector<vector<int>> dp;
vector<vector<pair<int, int>>> g;
bool solve(int x) {
vector<vector<int>> dstn(n, vector<int> (n, -inf));
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
if(dst[i][j] == inf)
continue;
dstn[i][j] = max(dstn[i][j], cst[i][j] - x * dst[i][j]);
}
}
for (int md = 0; md < n; md++) {
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
if(dstn[i][md] == -inf || dstn[md][j] == -inf)
continue;
dstn[i][j] = max(dstn[i][j], dstn[i][md] + dstn[md][j]);
}
}
}
for (int i = 0; i < n; i++) {
if(dstn[i][i] >= 0)
return 1;
}
return 0;
}
signed main() {
#ifdef PC
freopen("in.txt", "r", stdin);
freopen("out.txt", "w", stdout);
#endif
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n >> m >> k;
cst = vector<vector<int>> (n, vector<int> (n, 0));
dst = vector<vector<int>> (n, vector<int> (n, inf));
dst0 = vector<vector<int>> (n, vector<int> (n, inf));
s = vector<vector<int>> (n, vector<int> (k, 0));
b = vector<vector<int>> (n, vector<int> (k, 0));
for (int i = 0; i < n; i++) {
for (int j = 0; j < k; j++) {
cin >> b[i][j] >> s[i][j];
}
}
for (int i = 0; i < m; i++) {
int a, b, w;
cin >> a >> b >> w;
a--, b--;
dst[a][b] = min(dst[a][b], w);
}
for (int md = 0; md < n; md++) {
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
if(dst[i][k] < inf && dst[k][j] < inf)
dst[i][j] = min(dst[i][j], dst[i][k] + dst[k][j]);
}
}
}
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
dst0[j][i] = dst[i][j];
}
}
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
for (int z = 0; z < k; z++) {
if(b[i][z] == -1 || s[j][z] == -1)
continue;
cst[i][j] = max(cst[i][j], s[j][z] - b[i][z]);
}
}
}
int l = 0, r = infs;
while(r - l > 1) {
int mid = (l + r) / 2;
if(solve(mid))
l = mid;
else
r = mid;
}
cout << l << endl;
return 0;
}
