#include<fstream>
using namespace std;
ifstream fin("scmax.in");
ofstream gout("scmax.out");
long long n,i,j,m,k;
int v[2000000000];
int main ()
{fin>>n;
fin>>v[1];
m=v[1];
for (i=2;i<=n; i++)
{
	fin>>v[i];
	if (m>v[i])
		{m=v[i];k++;}
}
for (i=2;i<=n;i++)
{
	fin>>v[i];
	if (v[i]>m)
	{
		m=v[i];k++;
	}
}
gout<<k<<"\n";
fin>>v[1];
m=v[1];
for (i=2;i<=n; i++)
{
	fin>>v[i];
	if (m>v[i])
		{m=v[i];gout<<m<<" ";}
}
for (i=2;i<=n;i++)
{
	fin>>v[i];
	if (v[i]>m)
	{
		m=v[i];gout<<m<<" ";
	}
}
fin.close ();
gout.close ();
return 0;
}