#include<iostream>
#include<cassert>

using namespace std;
#define repeat(i,n) for(int i=0;i<(n);i++)

signed main(){

   int N, X;
   cin>> N>> X;
   int a[N];
   repeat(i, N) cin>> a[i];

   assert(1<=N and N<=100000);
   assert(0<=X and X<=1000000000);
   for(int e: a) assert(0<=e and e<=100000);

   cout<< -1<< endl;

   return 0;
}