#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define pos(i,a,b) for(int i=(a);i<=(b);i++)
#define N 301000
int n;
struct haha{
	int l,r,o;
}cun[N];
int ans[N];
bool aaa(const haha &a,const haha &b){
	if(a.l==b.l)
	   return a.r>b.r;
	return a.l<b.l;
}
int cnt;
void dfs(int now){
	cnt=now+1;int maxr=cun[now].l;
	int flag=0;
	while(cnt<=n&&maxr<cun[now].r){
		if(cun[cnt].r>cun[now].r)
		  break;
		if(!flag&&cun[cnt].l==maxr){
			maxr=max(maxr,cun[cnt].r);
		}
		else
		  flag=1;
		dfs(cnt);
	}
	if(maxr==cun[now].r){
		ans[now]=2;
	}
	else
	  ans[now]=1;
}
int sum;
int main(){
	scanf("%d",&n);
	pos(i,1,n){
		int x,y;
		scanf("%d%d",&x,&y);
		cun[i].o=x;cun[i].l=x-y;cun[i].r=x+y;
	}
	sort(cun+1,cun+n+1,aaa);
	pos(i,1,n){
		if(!ans[i])
		  dfs(i);
		sum+=ans[i];
	}
	cout<<sum+1;
	return 0;
}