#include<bits/stdc++.h>
using namespace std;

typedef struct point
{
	int l, r;
}point;

int a[100005],b[100005];
point A[100005];

bool cmp(point a,point b)
{
	return a.r<b.r;
}

int main()
{
	int n;
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		cin>>a[i]>>b[i];
		A[i].l=a[i]-b[i];
		A[i].r=a[i]+b[i];
	}
	sort(A+1,A+1+n,cmp);
	int tmp = -1000000001;
	int ans = 0;
	for(int i=1;i<=n;i++)
	{
		if(A[i].l>=tmp) 
		{
			ans++;
			tmp = A[i].r;
		}
	}
	cout<<ans;
	return 0;
}