#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
const int maxn = 105;
const int maxk = 1005;
const int maxm = 10005;
const ld eps = 0.0000001;
const ll inf = (ll)4e18;
ll b[maxn][maxk],s[maxn][maxk];
int n,m;
pair<pair<int,int>,ll> e[maxm], E[maxn*maxn];
ll dp[maxn][maxn];
ll c[maxn][maxn];
ld sp[maxn][maxn];
bool check(ll x){
memset(dp, 63, sizeof dp);
for (int i = 1; i <= n; i++)
dp[i][i] = 0;
for (int i = 1; i <= m; i++){
int v = e[i].first.first, u = e[i].first.second;
ll w = e[i].second;
dp[v][u] = x*w;
}
for (int k = 1; k <= n; k++)
for (int v = 1; v <= n; v++)
for (int u = 1; u <= n; u++)
dp[v][u] = min(dp[v][u], dp[v][k] + dp[k][u]);
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++)
if (i != j)
dp[i][j]-= c[i][j], sp[i][j] = dp[i][j] - eps;
for(int i = 1; i <= n; i++)
dp[i][i] = inf;
for(int k = 1; k <= n; k++)
for(int i = 1; i <= n; i++)
for(int j = 1; j <= n; j++)
dp[i][j] = min(dp[i][j], dp[i][k] + dp[k][j]);
for (int i = 1; i <= n; i++)
if (dp[i][i] <= 0)
return true;
return false;
}
int main() {
ios::sync_with_stdio(false), cin.tie(0);
int k;
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 v, u, w;
cin >> v >> u >> w;
e[i] = {{v, u}, w};
}
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++)
for (int x = 1; x <= k; x++)
if (b[i][x] != -1 and s[j][x] != -1)
c[i][j] = max(c[i][j], s[j][x] - b[i][x]);
ll lo = 0, hi = 1000 * 1000 * 1000 + 1;
while (hi - lo > 1){
ll mid = (lo + hi) >> 1;
if (check(mid))
lo = mid;
else
hi = mid;
}
cout << lo << endl;
}
