#include <algorithm>
#include <iostream>
#include <string.h>
#include <cstring>
#include <math.h>
#include <cmath>
#include <vector>
#include <utility>
#include <cstdlib>
#include <deque>
#include <queue>
#include <iomanip>
#include <stack>
#include <map>
#include <set>
#include <cmath>
#include <fstream>
#include <list>

using namespace std;


typedef long long ll;
const ll INF = 1e18;

ll n, s = 0, f, b[220], m;
vector <vector<pair<ll, ll> > > g(120);
vector<ll> d(120, INF), p(120);
set <pair<ll, ll> > q;


int main() {
    cin >> n;
    f = n - 1;
    for (int i = 0; i < n; i++)
        cin >> b[i];
    cin >> m;
    for (int i = 0; i < m; i++)
    {
        int t, y;
        cin >> t >> y;
        t--; y--;
        g[t].push_back(make_pair(y, b[t]));
        g[y].push_back(make_pair(t, b[y]));
    }
    d[s] = 0;
    q.insert(make_pair(d[s], s));
    while (!q.empty()) {
        int v = q.begin()->second;
        q.erase(q.begin());
        for (int j = 0; j < g[v].size(); ++j) {
            int to = g[v][j].first,
                len = g[v][j].second;
            if (d[v] + len < d[to]) {
                q.erase(make_pair(d[to], to));
                d[to] = d[v] + len;
                p[to] = v;
                q.insert(make_pair(d[to], to));
            }
        }
    }
    if(d[f] == INF)return cout << -1, 0;
    else cout << d[f];
}