#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <functional>
#include <set>
#include <ctime>
#include <random>
#include <chrono>
#include <cassert>
#include <tuple>
#include <utility>
using namespace std;

namespace {
  using Integer = long long; //__int128;
  template<class T, class S> istream& operator >> (istream& is, pair<T,S>& p){return is >> p.first >> p.second;}
  template<class T> istream& operator >> (istream& is, vector<T>& vec){for(T& val: vec) is >> val; return is;}
  template<class T> istream& operator ,  (istream& is, T& val){ return is >> val;}
  template<class T, class S> ostream& operator << (ostream& os, const pair<T,S>& p){return os << p.first << " " << p.second;}
  template<class T> ostream& operator << (ostream& os, const vector<T>& vec){for(size_t i=0; i<vec.size(); i++) os << vec[i] << (i==vec.size()-1?"":" "); return os;}
  template<class T> ostream& operator ,  (ostream& os, const T& val){ return os << " " << val;}

  template<class H> void print(const H& head){ cout << head; }
  template<class H, class ... T> void print(const H& head, const T& ... tail){ cout << head << " "; print(tail...); }
  template<class ... T> void println(const T& ... values){ print(values...); cout << endl; }

  template<class H> void eprint(const H& head){ cerr << head; }
  template<class H, class ... T> void eprint(const H& head, const T& ... tail){ cerr << head << " "; eprint(tail...); }
  template<class ... T> void eprintln(const T& ... values){ eprint(values...); cerr << endl; }

  class range{ Integer start_, end_, step_; public: struct range_iterator{ Integer val, step_; range_iterator(Integer v, Integer step) : val(v), step_(step) {} Integer operator * (){return val;} void operator ++ (){val += step_;} bool operator != (range_iterator& x){return step_ > 0 ? val < x.val : val > x.val;} }; range(Integer len) : start_(0), end_(len), step_(1) {} range(Integer start, Integer end) : start_(start), end_(end), step_(1) {} range(Integer start, Integer end, Integer step) : start_(start), end_(end), step_(step) {} range_iterator begin(){ return range_iterator(start_, step_); } range_iterator   end(){ return range_iterator(  end_, step_); } };

  inline string operator "" _s (const char* str, size_t size){ return move(string(str)); }
  constexpr Integer my_pow(Integer x, Integer k, Integer z=1){return k==0 ? z : k==1 ? z*x : (k&1) ? my_pow(x*x,k>>1,z*x) : my_pow(x*x,k>>1,z);}
  constexpr Integer my_pow_mod(Integer x, Integer k, Integer M, Integer z=1){return k==0 ? z%M : k==1 ? z*x%M : (k&1) ? my_pow_mod(x*x%M,k>>1,M,z*x%M) : my_pow_mod(x*x%M,k>>1,M,z);}
  constexpr unsigned long long operator "" _ten (unsigned long long value){ return my_pow(10,value); }

  inline int k_bit(Integer x, int k){return (x>>k)&1;} //0-indexed

  mt19937 mt(chrono::duration_cast<chrono::nanoseconds>(chrono::steady_clock::now().time_since_epoch()).count());

  template<class T> string join(const vector<T>& v, const string& sep){ stringstream ss; for(size_t i=0; i<v.size(); i++){ if(i>0) ss << sep; ss << v[i]; } return ss.str(); }

  inline string operator * (string s, int k){ string ret; while(k){ if(k&1) ret += s; s += s; k >>= 1; } return ret; }
}
constexpr long long mod = 9_ten + 7;

long long gcd(long long a, long long b){ return (b==0)?a:gcd(b,a%b); }
template<class ... T> long long gcd(long long a, long long b, T ... c){ return gcd(gcd(a,b), c...);}
template<class T> long long gcd(vector<T>& v){ long long g = v.front(); for(auto x : v) g=gcd(g,x); return g;}
long long lcm(long long a, long long b){ if(a<b) swap(a,b); return (b==1)?a:a*(b/gcd(a,b)); }
template<class ... T> long long lcm(long long a, long long b, T ... c){ return lcm(lcm(a,b), c...);}

int main(){
  int n;
  cin >> n;
  vector<long long> d(n);
  cin >> d;
  long long x,y;
  cin >> x,y;

  x = abs(x);
  y = abs(y);
  if(x<y) swap(x,y); //x>y

  if(!x && !y){
    println(0);
    return 0;
  }

  long long x_,y_;
  x_ = x+y;
  y_ =-x+y;

  auto d_ = d;
  for(auto& val : d_){
    val *= 2ll;
  }

  long long dist = abs(x_) + abs(y_);

  long long g = gcd(d_);

  if( dist%g != 0 ){
    println(-1);
    return 0;
  }

  dist /= g;
  for(auto& val : d_){
    val /= g;
  }

  long long ans = 1ll<<57;

  for(int i=0; i<n; i++){
    if( x%d[i] == 0 ) ans = min(ans, x/d[i]);
    else{
      long long t = x/d[i];
      if( t >= 2 ) t++;
      else t = 2;
      ans = min(ans, t);
    }
  }

  println(ans);

  return 0;
}