#include <cstdio>
#include <cctype>
#include <cstring>
#include <algorithm>
#include <vector>
typedef long long LL;
inline char fgc() {
static char buf[100000], *p1 = buf, *p2 = buf;
return p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, 100000, stdin), p1 == p2) ? EOF : *p1++;
}
inline LL readint() {
register LL res = 0, neg = 1;
register char c = fgc();
while(!isdigit(c)) {
if(c == '-') neg = -1;
c = fgc();
}
while(isdigit(c)) {
res = (res << 1) + (res << 3) + c - '0';
c = fgc();
}
return res * neg;
}
const int MAXN = 105, MAXK = 1005;
const LL INF = 0x3f3f3f3f3f3f3f3f;
int n, m, K;
LL gra[MAXN][MAXN], prof[MAXN][MAXN], b[MAXN][MAXK], s[MAXN][MAXK];
LL dis[MAXN][MAXN];
inline bool check(LL mid) {
memset(dis, 0x3f, sizeof(dis));
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= n; j++) {
if(gra[i][j] == INF) continue;
dis[i][j] = std::min(INF, gra[i][j] * mid - prof[i][j]);
}
dis[i][i] = INF;
}
for(int k = 1; k <= n; k++) {
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= n; j++) {
dis[i][j] = std::min(INF, std::min(dis[i][j], dis[i][k] + dis[k][j]));
}
if(dis[i][i] <= 0) return true;
}
}
return false;
}
int u, v;
LL w;
int main() {
memset(gra, 0x3f, sizeof(gra));
n = readint(); m = readint(); K = readint();
for(int i = 1; i <= n; i++) {
gra[i][i] = 0;
for(int j = 1; j <= K; j++) {
b[i][j] = readint(); s[i][j] = readint();
}
}
for(int i = 1; i <= m; i++) {
u = readint(); v = readint(); w = readint();
gra[u][v] = std::min(gra[u][v], w);
}
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= n; j++) {
for(int k = 1; k <= K; k++) {
if(b[i][k] == -1 || s[j][k] == -1) continue;
prof[i][j] = std::max(prof[i][j], s[j][k] - b[i][k]);
}
}
}
for(int k = 1; k <= n; k++) {
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= n; j++) {
gra[i][j] = std::min(gra[i][j], gra[i][k] + gra[k][j]);
}
}
}
LL l = 0, r = 1e15, mid;
while(r - l > 1) {
mid = (l + r) >> 1;
if(check(mid)) l = mid; else r = mid;
}
printf("%lld", l);
return 0;
}
