#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0; i<(n); i++)
using P = pair<int, int>;
constexpr int MX = 100005, INF = 2e9+5;
int n,x,l,a[MX];
P p[MX];
int main(){
	scanf("%d", &n);
	rep(i,n){
		scanf("%d%d", &x, &l);
		p[i] = {x+l,x-l};
	}
	sort(p,p+n);
	rep(i,n){
		l = p[i].second;
		auto it = lower_bound(p,p+n,P{l,INF});
		if(it != p) a[i] = a[it-1-p] + 1;
		else a[i] = 1;
		if(i) a[i] = max(a[i],a[i-1]);
	}
	printf("%d\n", a[n-1]);
}