using namespace std;
int ash[1000000];   
int akc[1000000];
long long possh[1000000];
long long poskc[1000000];
int main()
{
	int N, M;
	cin>>N>>M;
	int a, b;
	long long i, j;
	long long t(0);
	int f1, f2;
	long long ans(0);
	for (i=0;i<N;i++)
	{
		cin>>a>>b;
		t=t+b;
		for (j=t-b;j<t;j++)  
		{
			ash[j]=a;
		}
	}
	t=0;
	for (i=0;i<M;i++)
	{
		cin>>a>>b;
		t=t+b;
		for (j=t-b;j<t;j++) 
		{
			akc[j]=a;
		}
	}
	for (i=0;i<t;i++)
	{
		for (j=0;j<=i;j++)
		{
			possh[i]+=ash[j];
			poskc[i]+=akc[j];
		}
	}
	if (possh[0]>poskc[0])
	{
		f1=1;
	}
	else
	{
		f1=0;
	}
	for (i=1;i<t;i++)
	{
		if (possh[i]>poskc[i])
		{
			f2=1;
		}
		else
		{
			f2=0;                
		}
		if (f1!=f2)
		{
			ans=ans+1;
		}
		f1=f2;
	}
	cout<<ans; 
}```