#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<sstream>
#include<cmath>
#include<stack>
#include<cstdlib>
#include <vector>
#include<queue>
using namespace std;
#define ll long long
#define llu unsigned long long
#define INF 0x3f3f3f3f
#define PI acos(-1.0)
const int maxn = 1e5+5;
const int mod = 1e9+7;
int P,R,C;
int sum;
int p[1005],r[1005];
struct E
{
int u,v,w;
}e[20005];
struct Edge
{
int to, cap, flow;
int next;
}edge[4*maxn];
int tol;
int head[maxn];
int dep[maxn],pre[maxn],cur[maxn];
int gap[maxn];
void init()
{
tol = 0;
memset(head,-1,sizeof (head));
}
void addedge (int u,int v,int w,int rw=0)
{
edge[tol].to = v;
edge[tol].cap = w;
edge[tol].next = head[u];
edge[tol].flow = 0;
head[u] = tol++;
edge[tol].to = u;
edge[tol].cap = rw;
edge[tol]. next = head[v];
edge[tol].flow = 0;
head[v]=tol++;
}
int sap(int start,int end, int N)
{
memset(gap,0,sizeof(gap));
memset(dep,0,sizeof(dep));
memcpy(cur,head,sizeof(head));
int u = start;
pre[u] = -1;
gap[0] = N;
int ans = 0;
int i;
while(dep[start] < N)
{
if(u == end)
{
int Min = INF;
for( i = pre[u];i != -1; i = pre[edge[i^1]. to])
{
if(Min > edge[i].cap - edge[i]. flow)
Min = edge[i].cap - edge[i].flow;
}
for( i = pre[u];i != -1; i = pre[edge[i^1]. to])
{
edge[i].flow += Min;
edge[i^1].flow -= Min;
}
u = start;
ans += Min;
continue;
}
bool flag = false;
int v;
for( i = cur[u]; i != -1;i = edge[i].next)
{
v = edge[i]. to;
if(edge[i].cap - edge[i].flow && dep[v]+1 == dep[u])
{
flag = true;
cur[u] = pre[v] = i;
break;
}
}
if(flag)
{
u = v;
continue;
}
int Min = N;
for( i = head[u]; i != -1; i = edge[i]. next)
{
if(edge[i].cap - edge[i].flow && dep[edge[i].to] < Min)
{
Min = dep[edge[i].to];
cur[u] = i;
}
}
gap[dep[u]]--;
if(!gap[dep[u]])
return ans;
dep[u] = Min+1;
gap[dep[u]]++;
if(u != start)
u = edge[pre[u]^1].to;
}
return ans;
}
bool judge(int T) {
init();
for (int i = 1; i <= P; ++i) {
addedge(2 * i - 1, 2 * i, p[i]);
addedge(2 * i, 2 * P + 2 * R + 1, INF);
}
for (int i = 1; i <= C; ++i)
if(e[i].w<=T)
addedge(2*P+2*e[i].u,2*e[i].v-1,r[e[i].u]);
for(int i=1;i<=R;++i)
{
addedge(0,2*P+2*i-1,INF);
addedge(2*P+2*i-1,2*P+2*i,r[i]);
}
if(sap(0,2*P+2*R+1,2*P+2*R+2) == sum)
return true;
else
return false;
}
int main()
{
sum = 0;
scanf("%d%d%d",&P,&R,&C);
for(int i=1;i<=P;++i)
{
scanf("%d",p+i);
sum += p[i];
}
for(int i=1;i<=R;++i)
scanf("%d",r+i);
for(int i=1;i<=C;++i)
scanf("%d%d%d",&e[i].v,&e[i].u,&e[i].w);
int l = 1,r = 1000005;
bool flag = false;
while(l < r)
{
int mid = (l+r)/2;
if(judge(mid))
{
r = mid;
flag = true;
}
else
l = mid + 1;
}
if(flag)
printf("%d
",l);
else
puts("-1");
}