#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define pb push_back
#define LOOP(n) for(int rp=0;rp<(n);rp++)
#define sz(x) int(x.size())
#define bk(x) x.back()
#define dbg(x) cout << (#x) << " : " << x << endl
#define sdbg(x) cout << (#x) << " : " << x << "\n"
#define dbeg(x) cout << (#x) << " : " << x << ", "
#define sq(x) ((x)*(x))
#define lsb(x) ((x)&(-(x)))
#define sqm(x) mul((x),(x))
#define isnp(x) ((x)&((x)-1))
#define all(x) x.begin(),x.end()
#define fs first
#define sc second
#define fsh cout.flush()
using namespace std;
using namespace __gnu_pbds;
#define OS tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>
#define ofk order_of_key
//#pragma GCC optimize("trapv")
#pragma GCC optimize("Ofast","unroll-loops","O3")
#pragma GCC target("avx2")
mt19937_64 rng(time(0));
int rnd(int l,int r){
    return uniform_int_distribution<int>(l,r)(rng);
}
typedef long long ll;
typedef long double dl;
typedef unsigned long long ull;
const int SZ=5e5+7,MSZ=2e5+7;
const ll INF=1e18+7;
const dl eps=1e-18;
int MOD=1e9+7;
ll trig(ll n){
    return n*(n+1)/2;
}
int getN(){
    int n;cin >> n;
    return n;
}
int n,m,k;
ll B[107][1007],S[107][1007],F[107][107],C[107][107],dp[107][9907];
void FLOYED(){
    for(int X=0;X<=n+1;X++){
        for(int i=0;i<=n+1;i++){
            for(int j=0;j<=n+1;j++){
                F[i][j]=min(F[i][j],F[i][X]+F[X][j]);
            }
        }
    }
}
int32_t main(){
    ios_base::sync_with_stdio(0);cin.tie(0);
    //freopen("optmilk.in","r",stdin);
    //freopen("optmilk.out","w",stdout);
    //cout << fixed << setprecision(12);
    int tt=1;
    //cin >> tt;
    LOOP(tt){
        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 j=1;j<=n;j++){
                if(i==j)F[i][j]=0;
                else F[i][j]=INF;
            }
        }
        F[0][0]=F[n+1][n+1]=0;
        F[0][n+1]=F[n+1][0]=INF;
        for(int i=1;i<=n;i++){
            F[0][i]=F[i][n+1]=1;
            F[i][0]=F[n+1][i]=INF;

        }
        int mxW=0;
        LOOP(m){
            int x,y,w;cin >> x >> y >> w;
            F[x][y]=w;
            mxW=max(mxW,w);
        }
        FLOYED();
        if(mxW>1||n>50||k>50){
            ll ans=0;
            for(int v=1;v<=n;v++){
                for(int i=1;i<=n;i++){
                    if(v==i)continue;
                    for(int j=1;j<=k;j++){
                        if(S[i][j]==-1||B[v][j]==-1)continue;
                        ans=max(ans,(S[i][j]-B[v][j])/(F[v][i]+F[i][v]));
                    }
                }
            }
            cout << ans;
        }
        for(int v=1;v<=n;v++){
            for(int i=1;i<=n;i++){
                if(v==i)continue;
                for(int j=1;j<=k;j++){
                    if(S[i][j]==-1||B[v][j]==-1)continue;
                    C[v][i]=max(C[v][i],S[i][j]-B[v][j]);
                }
            }
        }
        ll ans=0;
        for(int X=1;X<=n;X++){
            for(int T=0;T<100;T++){
                if(T==0){
                    for(int i=1;i<=n;i++)dp[i][0]=-INF;
                    dp[X][0]=0;
                    continue;
                }
                for(int nd=1;nd<=n;nd++){
                    dp[nd][T]=-INF;
                    for(int pr=1;pr<=n;pr++){
                        if(pr==nd)continue;
                        if(F[pr][nd]>T)continue;
                        if(dp[pr][T-F[pr][nd]]==-INF)continue;
                        dp[nd][T]=max(dp[nd][T],dp[pr][T-F[pr][nd]]+C[pr][nd]);
                    }
                }
                ans=max(ans,dp[X][T]/T);
            }
        }
        cout << ans;
    }
    return 0;
}