#include <bits/stdc++.h>
using namespace std;

int main(){
  int n,m; assert(cin>>n>>m);

  for (int i=n; i--;) {int x; assert(cin>>x);}

  vector<set<int>> e(n);
  for (int i=m; i--;){
    int a,b; cin>>a>>b; --a,--b;
    if (not (0<=a and a<n) or not (0<=b and b<n)){
      cout<<"Edge "<<a+1<<" "<<b+1<<" is out of bounds"<<endl;
      return 43;
    }
//    if (e[a].count(b)){
//      cout<<"Edge "<<a+1<<" "<<b+1<<" is repeated in the input."<<endl;
//      return 43;
//    }
    e[a].insert(b);
    e[b].insert(a);
  }

  vector<bool> seen(n);
  queue<int> todo;
  todo.push(0);
  while (not todo.empty()){
    int x=todo.front(); todo.pop();
    for (auto y: e[x]){
      if (not seen[y]){
        seen[y]=true;
        todo.push(y);
      }
    }
  }

  if (not seen[1]){
    cout<<"Vertices 1 and 2 are not connected."<<endl;
    return 43;
  }

  return 42;
}