class MinCostFlow:
    def __init__(self, n):
        self.n = n
        self.G = [[] for i in range(n)]

    def addEdge(self, f, t, cap, cost):
        # [to, cap, cost, rev]
        self.G[f].append([t, cap, cost, len(self.G[t])])
        self.G[t].append([f, 0, -cost, len(self.G[f])-1])

    def minCostFlow(self, s, t, f):
        n = self.n
        G = self.G
        prevv = [0]*n; preve = [0]*n
        INF = 10**9+7

        res = 0
        while f:
            dist = [INF]*n
            dist[s] = 0
            update = 1
            while update:
                update = 0
                for v in range(n):
                    if dist[v] == INF:
                        continue
                    gv = G[v]
                    for i in range(len(gv)):
                        to, cap, cost, rev = gv[i]
                        if cap > 0 and dist[v] + cost < dist[to]:
                            dist[to] = dist[v] + cost
                            prevv[to] = v; preve[to] = i
                            update = 1
            if dist[t] == INF:
                return -1

            d = f; v = t
            while v != s:
                d = min(d, G[prevv[v]][preve[v]][1])
                v = prevv[v]
            f -= d
            res += d * dist[t]
            v = t
            while v != s:
                e = G[prevv[v]][preve[v]]
                e[1] -= d
                G[v][e[3]][1] += d
                v = prevv[v]
        return res
K,N,M=map(int,input().split())
A=list(map(int,input().split()))
G=[[] for i in range(N)]
B=list(map(int,input().split()))
for i in range(M):
  a,b,c=map(int,input().split())
  G[a-1].append((b-1,c))
  G[b-1].append((a-1,c))
from heapq import heappush,heappop
dist=[[10**16]*N for i in range(N)]
for i in range(N):
  dist[i][i]=0
  S=[]
  heappush(S,i)
  kaku=[False]*N
  while S:
    w=heappop(S)
    time=w//(10**4)
    x=w%(10**4)
    if kaku[x]==True:
      continue
    kaku[x]=True
    for B2 in G[x]:
      y,c=B2[:]
      if dist[i][y]>dist[i][x]+c:
        dist[i][y]=dist[i][x]+c
        heappush(S,dist[i][y]*10**4+y)
exit()
Z=MinCostFlow(K+N+2)
for i in range(1,K+1):
  Z.addEdge(0,i,1,0)
  pos=A[i-1]-1
  for j in range(N):
    Z.addEdge(i,j+1+K,1,dist[pos][j])
for j in range(N):
  Z.addEdge(j+1+K,N+K+1,B[j],0)
ans=Z.minCostFlow(0,N+K+1,K)
print(ans)