#include <bits/stdc++.h>
using namespace std;
int n, m, a[111], ans = 1e9;
set<int> s[111];
int main() {
  ios_base ::sync_with_stdio(false);
  cin >> n >> m;
  for (int i = 1; i <= n; ++i) {
    cin >> a[i];
  }
  for (int i = 0, x, y; i < m; ++i) {
    cin >> x >> y;
    s[x].insert(y);
    s[y].insert(x);
  }
  for (int i = 1; i < n - 1; ++i) {
    for (int j = i + 1; j < n; ++j) {
      if (s[i].count(j)) {
        for (int k = j + 1; k <= n; ++k) {
          if (s[i].count(k) && s[j].count(k)) {
            ans = min(a[i] + a[j] + a[k], ans);
          }
        }
      }
    }
  }
  if (ans == 1e9) {
    cout << -1;
  } else {
    cout << ans;
  }
}
