#include<bits/stdc++.h>
#define ShuaiBi main
using namespace std;
typedef long long ll;
const int N=1e5+3,M=2e5+3;
const ll inf=0x3f3f3f3f3f3f3f3f;
struct edge{
	int to,next;
	ll w;
}e[M<<1];
int head[N],ecnt=-1;
void add_edge(int u,int v,ll w){
	e[++ecnt].to=v; e[ecnt].next=head[u]; e[ecnt].w=w; head[u]=ecnt;
	e[++ecnt].to=u; e[ecnt].next=head[v]; e[ecnt].w=0; head[v]=ecnt;
}
int now[N],n,nn,m,k,s,t;
ll dis[N],cnt,sum,Ans;
bool bfs(){
	queue<int> q;
	memset(dis,0x3f,sizeof(dis));
	q.push(s),now[s]=head[s],dis[s]=0;
	while(!q.empty()){
		int x=q.front();
		q.pop();
		for(int i=head[x];~i;i=e[i].next){
			if(e[i].w>0 && dis[e[i].to]==inf){
				dis[e[i].to]=dis[x]+1;
				now[e[i].to]=head[e[i].to];
				q.push(e[i].to);
				if(e[i].to==t) return 1;
			}
		}
	}
	return 0;
}
ll dfs(int x,ll flow){
	if(x==t) return flow;
	ll k,res=0;
	for(int i=now[x];~i && flow;i=e[i].next){
		now[x]=i;
		if(e[i].w>0 && dis[e[i].to]==dis[x]+1){
			k=dfs(e[i].to,min(e[i].w,flow));
			if(k==0) dis[e[i].to]=inf;
			e[i].w-=k,e[i^1].w+=k;
			flow-=k,res+=k;
		}
	}
	return res;
}
ll dicnic(){
	ll ans=0;
	while(bfs()) ans+=dfs(s,inf);
	return ans;
}
bool boom[N];
int ShuaiBi(){
	memset(head,-1,sizeof(head));
	scanf("%d%d%d%d%d",&n,&m,&k,&s,&t);
	nn=2*n+1;
	for(int i=1,x;i<=n;i++){
		scanf("%d",&x),sum+=x;
		for(int j=0;j<k;j++){
			add_edge(i+j*nn,i+n+j*nn,x);
			for(int p=j+1;p<k;p++) add_edge(i+j*nn,i+n+p*nn,inf);
		}
	}
	for(int i=1,u,v;i<=m;i++){
		scanf("%d%d",&u,&v);
		for(int j=0;j<k;j++) add_edge(u+n+j*nn,v+j*nn,inf);
	}
	t=t+n+(k-1)*nn;
	if(sum<(Ans=dicnic())) return puts("-1"),0;
	bfs();
	for(int i=1;i<=n;i++)
		for(int j=0;j<k;j++)
			if(dis[i+j*nn]!=inf && dis[i+n+j*nn]==inf) cnt+=(!boom[i]),boom[i]=1;
	printf("%lld\n",cnt);
	for(int i=1;i<=t;i++) if(boom[i]) printf("%d ",i);
	putchar('\n');
	return 0;
}