/*
  author: honglan0301
  Sexy_goodier _ xiaoqing
 */
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cstdio>
#include <cctype>
#include <queue>
#include <map>
#include <unordered_map>
#include <cstdlib>
#include <ctime>
#include <vector>
#include <cmath>
#include <random>
#include <set>
#include <bitset>
#include <assert.h>
using namespace std;

//namespace Fread{const int SIZE=1<<20;char buf[SIZE],*S,*T;inline char getchar(){if(S==T){T=(S=buf)+fread(buf,1,SIZE,stdin);if(S==T)return'\n';}return*S++;}}using namespace Fread;namespace Fwrite{const int SIZE=1<<20;char buf[SIZE],*S=buf,*T=buf+SIZE;inline void flush(){fwrite(buf,1,S-buf,stdout);S=buf;}inline void putchar(char c){*S++=c;if(S==T)flush();}struct NTR{~NTR(){flush();}}ztr;}using namespace Fwrite;
//#define getchar Fread::getchar
//#define putchar Fwrite::putchar

namespace Fastio{struct Reader{template<typename T>Reader&operator>>(T&x){x=0;short f=1;char c=getchar();while(c<'0'||c>'9'){if(c=='-')f*=-1;c=getchar();}while(c>='0'&&c<='9')x=(x<<3)+(x<<1)+(c^48),c=getchar();x*=f;return*this;}Reader&operator>>(double&x){x=0;double t=0;short f=1,s=0;char c=getchar();while((c<'0'||c>'9')&&c!='.'){if(c=='-')f*=-1;c=getchar();}while(c>='0'&&c<='9'&&c!='.')x=x*10+(c^48),c=getchar();if(c=='.')c=getchar();else{x*=f;return*this;}while(c>='0'&&c<='9')t=t*10+(c^48),s++,c=getchar();while(s--)t/=10.0;x=(x+t)*f;return*this;}Reader&operator>>(long double&x){x=0;long double t=0;short f=1,s=0;char c=getchar();while((c<'0'||c>'9')&&c!='.'){if(c=='-')f*=-1;c=getchar();}while(c>='0'&&c<='9'&&c!='.')x=x*10+(c^48),c=getchar();if(c=='.')c=getchar();else{x*=f;return*this;}while(c>='0'&&c<='9')t=t*10+(c^48),s++,c=getchar();while(s--)t/=10.0;x=(x+t)*f;return*this;}Reader&operator>>(__float128&x){x=0;__float128 t=0;short f=1,s=0;char c=getchar();while((c<'0'||c>'9')&&c!='.'){if(c=='-')f*=-1;c=getchar();}while(c>='0'&&c<='9'&&c!='.')x=x*10+(c^48),c=getchar();if(c=='.')c=getchar();else{x*=f;return*this;}while(c>='0'&&c<='9')t=t*10+(c^48),s++,c=getchar();while(s--)t/=10.0;x=(x+t)*f;return*this;}Reader&operator>>(char&c){c=getchar();while(c==' '||c=='\n'||c=='\r')c=getchar();return*this;}Reader&operator>>(char*str){int len=0;char c=getchar();while(c==' '||c=='\n'||c=='\r')c=getchar();while(c!=' '&&c!='\n'&&c!='\r')str[len++]=c,c=getchar();str[len]='\0';return*this;}Reader&operator>>(string&str){str.clear();char c=getchar();while(c==' '||c=='\n'||c=='\r')c=getchar();while(c!=' '&&c!='\n'&&c!='\r')str.push_back(c),c=getchar();return*this;}Reader(){}}cin;const char endl='\n';struct Writer{const int Setprecision=6;typedef int mxdouble;template<typename T>Writer&operator<<(T x){if(x==0){putchar('0');return*this;}if(x<0)putchar('-'),x=-x;static short sta[40];short top=0;while(x>0)sta[++top]=x%10,x/=10;while(top>0)putchar(sta[top]+'0'),top--;return*this;}Writer&operator<<(double x){if(x<0)putchar('-'),x=-x;mxdouble _=x;x-=(double)_;static short sta[40];short top=0;while(_>0)sta[++top]=_%10,_/=10;if(top==0)putchar('0');while(top>0)putchar(sta[top]+'0'),top--;putchar('.');for(int i=0;i<Setprecision;i++)x*=10;_=x;while(_>0)sta[++top]=_%10,_/=10;for(int i=0;i<Setprecision-top;i++)putchar('0');while(top>0)putchar(sta[top]+'0'),top--;return*this;}Writer&operator<<(long double x){if(x<0)putchar('-'),x=-x;mxdouble _=x;x-=(long double)_;static short sta[40];short top=0;while(_>0)sta[++top]=_%10,_/=10;if(top==0)putchar('0');while(top>0)putchar(sta[top]+'0'),top--;putchar('.');for(int i=0;i<Setprecision;i++)x*=10;_=x;while(_>0)sta[++top]=_%10,_/=10;for(int i=0;i<Setprecision-top;i++)putchar('0');while(top>0)putchar(sta[top]+'0'),top--;return*this;}Writer&operator<<(__float128 x){if(x<0)putchar('-'),x=-x;mxdouble _=x;x-=(__float128)_;static short sta[40];short top=0;while(_>0)sta[++top]=_%10,_/=10;if(top==0)putchar('0');while(top>0)putchar(sta[top]+'0'),top--;putchar('.');for(int i=0;i<Setprecision;i++)x*=10;_=x;while(_>0)sta[++top]=_%10,_/=10;for(int i=0;i<Setprecision-top;i++)putchar('0');while(top>0)putchar(sta[top]+'0'),top--;return*this;}Writer&operator<<(char c){putchar(c);return*this;}Writer&operator<<(char*str){int cur=0;while(str[cur])putchar(str[cur++]);return*this;}Writer&operator<<(const char*str){int cur=0;while(str[cur])putchar(str[cur++]);return*this;}Writer&operator<<(string str){int st=0,ed=str.size();while(st<ed)putchar(str[st++]);return*this;}Writer(){}}cout;}using namespace Fastio;
#define cin Fastio::cin
#define cout Fastio::cout
#define endl Fastio::endl//;fflush(stdout)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define int long long
#define ll long long
#define ull unsigned long long
#define mod 998244353
#define G 3
#define Gi 332748118
mt19937 rnd(time(0));
mt19937_64 rndl(time(0));

int n,m,flag,lim;
pair<int,int> x[100005],y[100005];

struct tree
{
	int ls,rs,tag,len; ll sum;
}tree[10000005];
int cntd,rt;

#define ls(x) tree[x].ls
#define rs(x) tree[x].rs
#define l(x) tree[x].len
#define n(x) tree[x].sum
#define tg(x) tree[x].tag
#define md(x,y) ((x+y)>>1)
#define push_up(x) l(x)=l(ls(x))+l(rs(x)),n(x)=n(ls(x))+n(rs(x))
#define cz(k,p) tg(p)+=k,n(p)+=1ll*k*l(p)

void push_down(int p)
{
	if(tg(p))
	{
		if(!ls(p)) ls(p)=++cntd,l(ls(p))=(l(p)+1)/2; cz(tg(p),ls(p));
		if(!rs(p)) rs(p)=++cntd,l(rs(p))=l(p)/2; cz(tg(p),rs(p)); tg(p)=0;
	}
}
void cza(int l,int r,int x,int y,int k,int &p)
{
	if(!p) p=++cntd,l(p)=r-l+1; if(l>=x&&r<=y) return cz(k,p),void(); int mid=md(l,r); push_down(p);
	if(mid>=x) cza(l,mid,x,y,k,ls(p)); if(mid<y) cza(mid+1,r,x,y,k,rs(p)); push_up(p);
}
void czf(int l,int r,int k,int p)
{
	if(l==r) return n(p)-=k,void(); int mid=md(l,r); push_down(p);
	if(n(ls(p))<=k) czf(mid+1,r,k-n(ls(p)),rs(p)),ls(p)=0; else czf(l,mid,k,ls(p)); push_up(p);
}
int askm(int l,int r,int p)
{
	if(l==r) return l; int mid=md(l,r); push_down(p);
	if(n(ls(p))) return askm(l,mid,ls(p)); else return askm(mid+1,r,rs(p));
}

void ins(pair<int,int> xx,int k)
{
	if(xx.se>=k) return;
	cza(0,lim,xx.fi+xx.se,xx.fi+k-1,1,rt);
}
void del(pair<int,int> xx,int k)
{
	flag&=askm(0,lim,rt)>=xx.fi;
	if(n(rt)<=xx.se) rt=0; else czf(0,lim,xx.se,rt);
}

void clr()
{
	for(int i=1;i<=cntd;i++) ls(i)=rs(i)=n(i)=tg(i)=l(i)=0; cntd=rt=0;
}
int ck(int k)
{
	int nzl=1,nzr=1; flag=1;
	while(nzl<=n&&nzr<=m)
	{
		if(x[nzl].fi<y[nzr].fi) ins(x[nzl++],k);
		else del(y[nzr++],k);
	}
	while(nzl<=n) ins(x[nzl++],k);
	while(nzr<=m) del(y[nzr++],k);
	flag&=askm(0,lim,rt)==lim; clr(); return flag;
}

signed main()
{
	cin>>n>>m;
	for(int i=1;i<=n;i++) cin>>x[i].fi>>x[i].se;
	for(int i=1;i<=m;i++) cin>>y[i].fi>>y[i].se;
	sort(x+1,x+n+1); sort(y+1,y+m+1);
	int l=0,r=0;
	for(int i=1;i<=n;i++) r+=x[i].se;
	for(int i=1;i<=m;i++) r+=y[i].se; r/=n;
	lim=r+2000000000ll;
	while(l<=r)
	{
		int mid=(l+r)>>1;
		if(ck(mid)) l=mid+1; else r=mid-1;
	}
	cout<<r<<endl;
}