from collections import deque,defaultdict
N,M,K=map(int,input().split())
C=list(map(int,input().split()))
G=[[] for _ in range(N)]
D=defaultdict(int)
for i in range(M):
    u,v=map(int,input().split())
    u-=1;v-=1
    G[u].append(v)
    G[v].append(u)
    if u>v:u,v=v,u
    D[(u,v)]=C[i]
def dfs(route,cost):
    global ans
    now=route[-1]
    if now==N-1:
        cost=sorted(cost)
        ans=min(ans,sum(cost[:max(1,len(cost)-K)]))
        return
    for nxt in G[now]:
        if nxt in route:continue
        if now>nxt:dfs(route+(nxt,),cost+(D[(nxt,now)],))
        else:dfs(route+(nxt,),cost+(D[(now,nxt)],))
ans=1<<60
dfs((0,),(0,))
if ans<1<<60:print(ans)
else:print(-1)