# include<iostream>
# include<fstream>
# include<cmath>
using namespace std;
int main()
{
int n, a[10]={0},x,i,ok=0;
ifstream fisier("bac.txt");
fisier>>n;
while(fisier>>x)
a[(int)log2(x)]++;
fisier.close();
x=0;
for(i=9;i>=0;i--)
{
if(a[i]>0)
x++;
if(x==n)
{
cout<<pow(2,i);
ok=1;
break;
}
}
if(ok==0)
cout<<"Nu exista";
return 0;
}