// Problem: B. 小游戏
// Contest: undefined - NOIP2024训练赛 02
// URL: http://noi.ac/contest/1154/problem/2058
// Memory Limit: 1024 MB
// Time Limit: 1000 ms
// Challenger: Erica N
// ----
// 
#include<bits/stdc++.h>

using namespace std;
#define rd read()
#define ull unsigned long long
#define int long long 
#define pb push_back
#define itn int
#define ps second 
#define pf first


#define rd read()
int read(){
  int xx = 0, ff = 1;char ch = getchar();
  while (ch < '0' || ch > '9'){
    if (ch == '-')ff = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9')xx = xx * 10 + (ch - '0'), ch = getchar();
  return xx * ff;
}
#define zerol = 1
#ifdef zerol
#define cdbg(x...) do { cerr << #x << " -> "; err(x); } while (0)
void err() {cerr << endl;}
template<template<typename...> class T, typename t, typename... A>
void err(T<t> a, A... x) {
	for (auto v: a) cerr << v << ' ';err(x...);
}
template<typename T, typename... A>
void err(T a, A... x) {
	cerr << a << ' ';err(x...);
}
#else
#define dbg(...)
#endif
const int N=2e5+5;
const ull P=137;
const int INF=1e18+7;
/*

策略


*/	




struct Node{
	int v,w;
};vector<Node> e[N];

int d[N],g[N];
int n,m,V;
int w[N];

void add(int c,int b,int a){
	e[a].pb({b,c});
	e[b].pb({a,c});
}

struct Suff{
	int v,d,g;
	bool operator<(const Suff b)const{
		return d>b.d;
	}
};

priority_queue<Suff> q;

void spfa(){
	memset(d,0x3f3f,sizeof d);
	d[1]=0;
	g[1]=V;
	
	q.push({1,0,V});
	while(q.size()){
		int x=q.top().v;
		int dd=q.top().d;
		int gg=q.top().g;
		q.pop();
		if(x==n){
			cout<<dd;;
			exit(0) ;
		}
		for(auto v:e[x]){
			if(g[v.v]>=min(V,gg-v.w+w[v.v])||gg-v.w<=0)continue;
			g[v.v]=min(V,gg-v.w+w[v.v]);
			d[v.v]=dd+1;
			q.push({v.v,d[v.v],g[v.v]});
		}
	}
	
}

signed main(){
	 n=rd,m=rd,V=rd;
	 
	 for(int i=1;i<=n;i++){
	 	w[i]=rd;
	 }
	for(int i=1;i<=m;i++){
		add(rd,rd,rd);
	}
	
	
	spfa();
	
	cout<<-1;
}