#include<iostream>
#include<cstdio>
#include<vector>
#include<queue>

using namespace std;

const int maxn = 40000 + 100;

int a;
int b;
int k;

int C[maxn];
int B[maxn];

struct T
{
	int next;
	int to;
	int w;
}A[maxn];

int kount = 0;

int head[maxn];

int vis[maxn];//点

int vis1[maxn];//bian 

int dis[maxn];

queue<int >q;

int ans = 0;

int u;
int v;
int W;

inline void adde(int a,int b,int w)
{
	A[++ kount].next = head[a];
	A[kount].to = b;
	A[kount].w = w;
	head[a] = kount;
}

inline void bfs(int x)
{
	q.push(x);
	vis[x] = 1;
	dis[x] = 0;
	while(!q.empty())
	{
		int t = q.front();
		q.pop();
		vis[t] = 0;
		vis1[A[t].next] = 1;
		for(int i = head[t];i;i = A[i].next)
		{
			int u = A[i].to;
			/*
			if(dis[u] < dis[t] + A[i].w)
			{
				dis[u] = dis[t] + A[i].w;
				if(!vis[u])
				{
					q.push(u);
					vis[u] = 1;
				}
			}
			*/
			if(!vis1[A[u].next])
			{
				if(dis[u] < dis[t] + A[i].w)
				{
					dis[u] = dis[t] + A[i].w;
					if(!vis[u])
					{
						q.push(u);
						vis[u] = 1;
					}
				}
			}
		}
	}
}

int main()
{
	freopen("meibridge.in","r",stdin);
	freopen("meibridge.out","w",stdout);
	scanf("%d%d%d",&a,&b,&k);
	for(int i = 1;i <= a ;i ++)
	{
		scanf("%d",&C[i]);
	}
	for(int i = 1;i <= b ;i ++)
	{
		scanf("%d",&B[i]);
	}
	for(int i = 0;i < k ;i ++)
	{
		scanf("%d%d",&u,&v);
		W = C[u] + B[v];
		adde(u,v,W);
		adde(v,u,W);
	}
	bfs(1);
	for(int i = 1;i <= (a + b) / 2 ;i ++)
	{
		ans = max(ans,dis[i]);
	}
	cout<<ans + a + b;
	return 0;
}