// File Name: 10246.cpp
// Author: Zlbing
// Created Time: 2013/4/18 17:37:24

#include<iostream>
#include<string>
#include<algorithm>
#include<cstdlib>
#include<cstdio>
#include<set>
#include<map>
#include<vector>
#include<cstring>
#include<stack>
#include<cmath>
#include<queue>
using namespace std;
#define CL(x,v); memset(x,v,sizeof(x));
#define INF 0x3f3f3f3f
#define LL long long
#define REP(i,r,n) for(int i=r;i<=n;i++)
#define RREP(i,n,r) for(int i=n;i>=r;i--)
const int MAXN=105;int C,R,Q;
int P[MAXN];
struct Edge{int u,v,cost;
};
vector<Edge> edges;
vector<int> G[MAXN];
struct node{int u,cost;bool operator <(const node& rhs)const{return cost>rhs.cost;}
};
int V[MAXN][MAXN];
void dijkstra(int st)
{priority_queue<node> Q;node t,tt;t.u=st;t.cost=0;Q.push(t);memset(V[st],-1,sizeof(V[st]));V[st][t.u]=0;while(!Q.empty()){t=Q.top();Q.pop();for(int i=0;i<G[t.u].size();i++){Edge e=edges[G[t.u][i]];tt.u=e.v;tt.cost=t.cost+e.cost;if((V[st][e.v]==-1||V[st][e.v]>tt.cost)&&P[e.v]<=P[st]){V[st][e.v]=tt.cost;Q.push(tt);}}}
}
int main()
{int cas=0;//freopen("out.txt","w",stdout);while(~scanf("%d%d%d",&C,&R,&Q)){if(C==0&&R==0&&Q==0)break;if(cas)printf("\n");REP(i,1,C){scanf("%d",&P[i]);}REP(i,1,C)G[i].clear();edges.clear();printf("Case #%d\n",++cas);REP(i,1,R){int a,b,c;scanf("%d%d%d",&a,&b,&c);edges.push_back((Edge){a,b,c});edges.push_back((Edge){b,a,c});int m=edges.size();G[a].push_back(m-2);G[b].push_back(m-1);}REP(i,1,C)dijkstra(i);REP(i,1,Q){int a,b;scanf("%d%d",&a,&b);int ans=INF;REP(i,1,C){if(V[i][a]==-1||V[i][b]==-1)continue;ans=min(ans,V[i][a]+V[i][b]+P[i]);}if(ans==INF)printf("-1\n");elseprintf("%d\n",ans);}}return 0;
}