#include<bits/stdc++.h>
using namespace std;
const int N=2e5+5;
typedef long long ll;
int n,m,a[N],b[N],va,vb,pa,pb,h[N];
ll s[N];
ll bf(int i,int j,int d){
	ll res=0;
	for(int k=1;k<=i;++k)res+=min(j,h[k]);
	for(int k=i+1;k<=n;++k)res+=m-max(j,h[k]);
	return res;
}
bool check(int d){
	ll mx1=0,mx2=0,v;
	for(int i=0,j=m;i<=n;++i){
		v=1ll*i*j+1ll*(n-i)*(m-j);
		mx1=max(mx1,v);
		mx2=max(mx2,v-(pa<=i&&pb<=j||pa>i&&pb>j));
		while(j&&a[i+1]+b[j]>d)--j;
		h[i+1]=j;
		v=1ll*i*j+1ll*(n-i)*(m-j);
		mx1=max(mx1,v);
		mx2=max(mx2,v-(pa<=i&&pb<=j||pa>i&&pb>j));
		//printf("%lld %lld %lld %d %d %d %d %d\n",v,mx1,mx2,d,i,j,pa,pb);
	}
	mx2=max(mx2,bf(pa,pb-1,d));
	mx2=max(mx2,bf(pa-1,pb,d));
	return mx1!=mx2+1;
}
int main(){
	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]);
	va=a[1],vb=b[1];
	sort(a+1,a+n+1);
	sort(b+1,b+m+1);
	pa=lower_bound(a+1,a+n+1,va)-a;
	pb=lower_bound(b+1,b+m+1,vb)-b;
	int l=1,r=va+vb;
	while(l<r){
		int mid=l+r>>1;
		if(check(mid))r=mid;
		else l=mid+1;
	}
	printf("%d\n",l);
	return 0;
}