#include<cstdio>

#include<algorithm>

using namespace std;

int n,m,a[100100],b[100100];

int main()

{

	//freopen("h.in","r",stdin);

	scanf("%d%d",&n,&m);

	for(int i=1;i<=n;++i)

	  scanf("%d",&a[i]);

	for(int i=1;i<=m;++i)

	  scanf("%d",&b[i]);

	int ans=0;

	for(int i=2;i<n;++i)

	  ans=max(min(b[1],min(b[m],a[i])),ans);

	ans=max(ans,min(a[1],b[m]));

	ans=max(ans,min(b[1],a[n]));

	for(int i=2;i<m;++i)

	  ans=max(min(a[1],min(a[n],b[i])),ans);

	printf("%d\n",ans);

	return 0;

}