#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define debug(x) cout << #x << " = " << x << " ";
#define fast ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
#define S second
#define F first
using namespace std;
const int maxn = 1e2 + 10 , maxk = 1e3 + 10;
const ll int inf = 1e18 + 10;
int n , m , k , s[maxn][maxk] , b[maxn][maxk];
ll dis[maxn][maxn] , ans[maxn][maxn];
vector <pair<ll, int>> g[maxn];
void allinf(ll tmp[maxn][maxn])
{
for(int i = 0 ; i < n ; i++)
for(int j = 0 ; j < n ; j++)
tmp[i][j] = inf;
}
void floyd(ll dist[maxn][maxn])
{
for(int i = 0 ; i < n ; i++)
for(auto u : g[i])
dist[i][u.S] = min(dist[i][u.S] , u.F);
for(int kk = 0 ; kk < n ; kk++)
for(int i = 0 ; i < n ; i++)
for(int j = 0 ; j < n ; j++)
dist[i][j] = min(dist[i][j] , dist[i][kk] + dist[kk][j]);
for(int i = 0 ; i < n ; i++)
for(int j = 0 ; j < n ; j++)
dist[i][j] = min(dist[i][j] , dist[i][n - 1] + dist[n - 1][j]);
}
int c(int v , int u)
{
int res = 0;
for(int i = 0 ; i < k ; i++)
if(b[v][i] != -1 && s[u][i] != -1)
res = max(res , b[v][i] - s[u][i]);
return res;
}
int main()
{
cin >> n >> m >> k;
for(int i = 0 ; i < n ; i++)
for(int j = 0 ; j < k ; j++)
cin >> s[i][j] >> b[i][j];
for(int i = 0 ; i < m ; i++)
{
int v , u , w;
cin >> v >> u >> w;
v--; u--;
g[v].pb({w , u});
}
allinf(dis);
floyd(dis);
ll low = 0 , high = inf;
while(high - low > 1)
{
ll mid = (high + low) / 2;
for(int i = 0 ; i < n ; i++) g[i].clear();
for(int i = 0 ; i < n ; i++)
for(int j = 0 ; j < n ; j++)
if(i != j)
g[i].pb({1LL * mid * dis[i][j] - c(i , j) , j});;
allinf(ans);
floyd(ans);
ll mn = 667;
for(int i = 0 ; i < n ; i++) mn = min(mn , ans[i][i]);
if(mn < 1)
low = mid;
else
high = mid;
}
cout << low << endl;
return 0;
}
