#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;
struct runner//跑者 
{
	int t=0;
	int v=0;//v 
};
runner h[1005];
runner c[1005];
int main()
{
	int n=0,m=0;
	cin>>n>>m;
	for(int i=1;i<=n;i++)
	{
		cin>>h[i].v>>h[i].t;	
	}
	for(int i=1;i<=m;i++)
	{
		cin>>c[i].v>>c[i].t;
	}
	int i=1;
	int j=1;
	int hs=0;
	int cs=0;
	int change=2;
	int ans=0;
	int tw=1;
	while(i<=n&&j<=m)
	{
		if(h[i].t<=0)
		{
			i++;	
		}
		else if(c[j].t<=0)
		{
			j++;
		}
		hs+=h[i].v;
		cs+=c[j].v;
		if(hs>cs&&change!=0)
		{
			if(tw!=1)
			{
				ans++;
			}
			change=0;
			
			tw++;
		}
		else if(hs<cs&&change!=1)
		{
			if(tw!=1)
			{
				ans++;
			}
			change=1;
			
			tw++;
		}
		h[i].t--;
		c[j].t--;
	}
	cout<<ans;
}