/*
_____
.' '.
/ 0 0 \
| ^ |
| \ / |
\ '---' /
'._____.'
*/
#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/rope>
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
random_device(rd);
mt19937 rng(rd());
const long long FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
struct custom_hash
{
template<class T>
unsigned long long operator()(T v) const
{
unsigned long long x = v;
x += FIXED_RANDOM; x += 11400714819323198485ull;
x = (x ^ (x >> 30)) * 13787848793156543929ull;
x = (x ^ (x >> 27)) * 10723151780598845931ull;
return x ^ (x >> 31);
}
};
template<class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<class T, class U> using hash_table = gp_hash_table<T, U, custom_hash>;
template<class T>
void readi(T &x)
{
x = 0;
bool negative = false;
char c = ' ';
while (c < '-')
{
c = getchar();
}
if (c == '-')
{
negative = true;
c = getchar();
}
while (c >= '0')
{
x = x * 10 + (c - '0');
c = getchar();
}
if (negative)
{
x = -x;
}
}
template<class T>
void printi(T output)
{
if (output == 0)
{
putchar('0');
return;
}
if (output < 0)
{
putchar('-');
output = -output;
}
int buf[20], n = 0;
while(output)
{
buf[n] = ((output % 10));
output /= 10;
n++;
}
for (n--; n >= 0; n--)
{
putchar(buf[n] + '0');
}
return;
}
template<class T>
void ckmin(T &a, T b)
{
a = min(a, b);
}
template<class T>
void ckmax(T &a, T b)
{
a = max(a, b);
}
long long expo(long long a, long long e, long long mod)
{
return ((e == 0) ? 1 : ((expo(a * a % mod, e >> 1, mod)) * ((e & 1) ? a : 1) % mod));
}
template<class T, class U>
T nmod(T &x, U mod)
{
if (x >= mod) x -= mod;
}
template<class T>
T gcd(T a, T b)
{
return (b ? gcd(b, a % b) : a);
}
template<class T>
T randomize(T mod)
{
return (uniform_int_distribution<T>(0, mod - 1))(rng);
}
#define y0 ___y0
#define y1 ___y1
#define MP make_pair
#define MT make_tuple
#define PB push_back
#define PF push_front
#define fi first
#define se second
#define debug(x) cerr << #x << " = " << x << endl;
#define sz(x) ((int) (x.size()))
const long double PI = 4.0 * atan(1.0);
const long double EPS = 1e-9;
#define MAGIC 347
#define SINF 10007
#define CO 1000007
#define INF 1000000007
#define BIG 1000000931
#define LARGE 1696969696967ll
#define GIANT 2564008813937411ll
#define LLINF 2696969696969696969ll
#define MAXN 113
#define MAXK 1013
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<ld, ld> pdd;
int N, M, K;
vector<pair<ll, int> > edge[MAXN];
ll sell[MAXN][MAXK], buy[MAXN][MAXK];
ll dist[MAXN][MAXN], profit[MAXN][MAXN];
ll dp[MAXN][MAXN];
bool check(ll k)
{
//earn / dist >= k => earn >= dist * k => earn - dist * k >= 0
for (int i = 0; i < N; i++)
{
for (int j = 0; j < N; j++)
{
dp[i][j] = -LLINF;
if (i == j || dist[i][j] == LLINF || profit[i][j] == -LLINF) continue;
dp[i][j] = profit[i][j] - dist[i][j] * k;
}
}
for (int k = 0; k < N; k++)
{
for (int i = 0; i < N; i++)
{
for (int j = 0; j < N; j++)
{
ckmax(dp[i][j], dp[i][k] + dp[k][j]);
}
}
}
for (int i = 0; i < N; i++)
{
if (dp[i][i] >= 0)
{
return true;
}
}
return false;
}
int32_t main()
{
// ios_base::sync_with_stdio(0); cin.tie(0);
// cout << fixed << setprecision(10);
// cerr << fixed << setprecision(10);
// freopen ("file.in", "r", stdin);
// freopen ("file.out", "w", stdout);
readi(N); readi(M); readi(K);
for (int i = 0; i < N; i++)
{
for (int j = 0; j < K; j++)
{
readi(buy[i][j]); readi(sell[i][j]); //buy, sell
if (buy[i][j] == -1) buy[i][j] = LLINF;
if (sell[i][j] == -1) sell[i][j] = -LLINF;
}
}
for (int i = 0; i < N; i++)
{
for (int j = 0; j < N; j++)
{
dist[i][j] = LLINF;
profit[i][j] = 0;
}
dist[i][i] = 0;
}
for (int i = 0; i < M; i++)
{
int u, v; ll d;
readi(u); readi(v); readi(d); u--; v--;
ckmin(dist[u][v], d);
}
for (int k = 0; k < N; k++)
{
for (int i = 0; i < N; i++)
{
for (int j = 0; j < N; j++)
{
ckmin(dist[i][j], dist[i][k] + dist[k][j]);
}
}
}
for (int i = 0; i < N; i++)
{
for (int j = 0; j < N; j++)
{
for (int k = 0; k < K; k++)
{
ckmax(profit[i][j], sell[j][k] - buy[i][k]);
}
// cerr << profit[i][j] << ' ';
}
// cerr << endl;
}
// for (int i = 0; i < N; i++)
// {
// for (int j = 0; j < N; j++)
// {
// cerr << profit[i][j] << ' ';
// }
// cerr << endl;
// }
// for (int i = 0; i < N; i++)
// {
// for (int j = 0; j < N; j++)
// {
// cerr << dist[i][j] << ' ';
// }
// cerr << endl;
// }
//for every pair (u, v) calculate minimum distance and maximum profit
ll lo = 0, hi = INF;
while(hi > lo)
{
int mid = (hi + lo + 1) >> 1;
if (check(mid))
{
lo = mid;
}
else
{
hi = mid - 1;
}
}
printi(lo); putchar('\n');
// cerr << "time elapsed = " << (clock() / (CLOCKS_PER_SEC / 1000)) << " ms" << endl;
return 0;
}
