#include<bits/stdc++.h>
using namespace std;
#define f first
#define s second
typedef long long ll;
const int maxn = 1005;
const ll inf = 1e18;
ll w[maxn][maxn], d[maxn][maxn], d2[maxn][maxn], best[maxn][maxn], prc[2][maxn][maxn];
int n, m, K;
bool chk(ll x){
for(int i = 1; i <= n; i++){
for(int j = 1; j <= n; j++){
if(d[i][j] < inf){
d2[i][j] = d[i][j]*x - best[i][j];
d2[i+n][j+n] = d2[i][j];
if(i != j){
d2[i+n][j] = d2[i][j];
d2[i][j+n] = d2[i][j];
}
}
else d2[i][j] = inf;
}
}
for(int k = 1; k <= 2*n; k++){
for(int i = 1; i <= 2*n; i++){
for(int j = 1; j <= 2*n; j++)if(d2[i][k] < inf && d2[k][j] < inf)d2[i][j] = min(d2[i][j], d2[i][k]+d2[k][j]);
}
}
for(int i = 1; i <= n; i++)if(d2[i][i+n] < 0)return 1;
return 0;
}
int main(){
cin >> n >> m >> K;
for(int i = 1; i <= n; i++){
for(int j = 1; j <= K; j++){
for(int l = 0; l < 2; l++)cin >> prc[l][i][j];
}
}
for(int i = 1; i <= n; i++){
for(int j = 1; j <= n; j++)d[i][j] = i == j ? 0 : inf;
}
for(int i = 0; i < m; i++){
ll a, b, w;
cin >> a >> b >> w;
d[a][b] = min(d[a][b], w);
}
for(int k = 1; k <= n; k++){
for(int i = 1; i <= n; i++){
for(int j = 1; j <= n; j++)d[i][j] = min(d[i][j], d[i][k]+d[k][j]);
}
}
for(int i = 1; i <= n; i++){
for(int j = 1; j <= n; j++){
if(d[i][j] < inf){
for(int l = 1; l <= K; l++){
if(prc[0][i][l] >= 0 && prc[1][j][l] > 0)best[i][j] = max(best[i][j], prc[1][j][l] - prc[0][i][l]);
}
}
}
}
ll l = 0, r = 1e9;
while(l < r){
ll mid = (l+r+1)>>1;
if(chk(mid))l = mid;
else r = mid-1;
}
cout << l;
}
