#include <bits/stdc++.h>
#define rep(i,a,b) for (auto i = (a); i <= (b); ++i)
#define Mup(x,y) x = max(x,y)
#define mup(x,y) x = min(x,y)
#define all(x) begin(x),end(x)
#define per(i,a,b) for (auto i = (b); i >= (a); --i)
using namespace std;
using ll = long long;
using ii = pair<int,int>;
#define dbg(...) fprintf(stderr,__VA_ARGS__)
const ll INF = 1e18;
const int N = 1e5+3;
int n, m, x, h[N];
vector<ii> adj[N];
ll k[N];
int main() {
scanf("%d%d%d", &n, &m, &x);
assert(!x);
rep(i,1,n) scanf("%d", &h[i]);
rep(i,1,m) {
int u, v, t;
scanf("%d%d%d", &u, &v, &t);
adj[u].push_back({v,t});
adj[v].push_back({u,t});
}
fill(k,k+N,INF);
priority_queue<pair<ll,int>> pq;
k[1] = 0, pq.push({0,1});
while (not empty(pq)) {
auto [d,a] = pq.top(); pq.pop(), d=-d;
if (k[a] < d) continue;
for (auto [b,t] : adj[a]) {
if (h[a] >= t and k[b] > k[a]+2*t) {
k[b] = k[a]+2*t;
pq.push({-k[b],b});
}
}
}
if (h[n]+k[n] >= INF) puts("-1");
else printf("%lld", h[n]+k[n]);
// rep(i,1,n) dbg("%lld ", k[i]);
}
