#include<cstdio>

#include<cstring>

#include<algorithm>

using namespace std;

#define N 500050

#define ll long long

inline ll rd()

{

    ll f=,c=;char ch=getchar();

    while(ch<''||ch>''){if(ch=='-')f=-;ch=getchar();}

    while(ch>=''&&ch<=''){c=*c+ch-'';ch=getchar();}

    return f*c;

}

int n0,m0,n,m;

struct Pair

{

    ll x,y;

    Pair(){}

    Pair(ll x,ll y):x(x),y(y){}

};

bool cmp1(Pair a,Pair b)

{

    if(a.x!=b.x)return a.x<b.x;

    return a.y<b.y;

}

bool cmp2(Pair a,Pair b)

{

    if(a.x!=b.x)return a.x<b.x;

    return a.y>b.y;

}

Pair a0[N],b0[N],a[N],b[N];

ll ans = ;

void divi(int l1,int r1,int l2,int r2)

{

    if(l1>r1||l2>r2)return ;

    if(l1==r1)

    {

        for(int i=l2;i<=r2;i++)

            if(b[i].x>a[l1].x)ans = max(ans,(b[i].x-a[l1].x)*(b[i].y-a[l1].y));

        return ;

    }

    if(l2==r2)

    {

        for(int i=l1;i<=r1;i++)

            if(b[l2].x>a[i].x)ans = max(ans,(b[l2].x-a[i].x)*(b[l2].y-a[i].y));

        return ;

    }

    int mid = (l2+r2)>>;

    int pos=l1;

    ll max_val=-0x3f3f3f3f3f3f3f3fll;

    for(int i=l1;i<=r1;i++)

    {

        if(b[mid].x<=a[i].x&&b[mid].y<=a[i].y)continue;

        if((b[mid].x-a[i].x)*(b[mid].y-a[i].y)>max_val)

        {

            pos = i;

            max_val=(b[mid].x-a[i].x)*(b[mid].y-a[i].y);

        }

    }

    ans=max(ans,max_val);

    divi(l1,pos,l2,mid-);

    divi(pos,r1,mid+,r2);

}

int main()

{

//  freopen("33.in","r",stdin);

    n0 = rd(),m0 = rd();

    for(int i=;i<=n0;i++)

        a0[i].x = rd(),a0[i].y = rd();

    for(int i=;i<=m0;i++)

        b0[i].x = rd(),b0[i].y = rd();

    sort(a0+,a0++n0,cmp1);

    sort(b0+,b0++m0,cmp2);

    ll lim = 0x3f3f3f3f3f3f3f3fll;

    for(int i=;i<=n0;i++)

        if(a0[i].y<lim)

        {

            a[++n]=a0[i];

            lim = a0[i].y;

        }

    for(int i=;i<=m0;i++)

    {

        while(m&&b[m].y<=b0[i].y)m--;

        b[++m]=b0[i];

    }

    divi(,n,,m);

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

    return ;

}