#include <iostream>
#include <math.h>
#include <vector>
#include <string>
#include <algorithm>
#include <queue>
#include <stack>
#include <map>
#include <cstring>
#include <iomanip>
#include <set>
#include <bitset>
using namespace std;
using ll = long long;
using pii = pair<int,int>;
using piii = tuple<int,int,int>;
#define endl '\n'
#define f first
#define s second
int main(){
int n;cin >> n;
vector<pii> vc;
for(int i{};i < n;i++){
int a,b;cin >> a >> b;
vc.emplace_back(b,a);
}
vector<bool> visit(n,false);
sort(vc.begin(),vc.end(),greater<pii>());
int cnt = 0;
for(int i{};i < n;i++){
if(!visit[i]){
visit[i] = 1;
cnt++;
//cout << endl << i << endl;
for(int j{i+1};j < n;j++){
if(visit[j]) continue;
if(abs(vc[i].s-vc[j].s) <= vc[i].f-vc[j].f){
//cout << j << " ";
visit[j] = 1;
}
}
}
}
cout << cnt;
}
