#include<iostream>
#include<cassert>
using namespace std;

#define rep(i,n) for(int i=0;i<(n);i++)

int main(){

  int n; cin>> n;
  assert(1<=n and n<=17);
  rep(_, n){
    int a, b; cin>> a>> b;
    assert(1<=a and a<=100000);
    assert(1<=b and b<=100000);
  }

  cout<< -1<< endl;
  return 0;
}