// prea multe comentarii
#include <bits/stdc++.h>
#define int long long
using namespace std;
const int nmax = 1e5 + 1;
struct str {
int a, b;
const bool operator < (str ult) const {
if(b != ult.b) {
return b < ult.b;
}
return a < ult.a;
}
} v[nmax];
bool f[nmax];
int32_t main() {
int n;
cin >> n;
set<str> ms;
for(int i = 1; i <= n; i ++) {
cin >> v[i].a >> v[i].b;
//cout << "bag " << v[i].a << " " << v[i].b << endl;
ms.insert({v[i].a, v[i].b});
}
int ans = 0;
while(!ms.empty()) {
//cout << endl;
//cout << "la inceput:\n";
//for(auto it : ms) {
//cout << it.a << " " << it.b << "\n";
//}
auto it = ms.rbegin();
ans ++;
int ita = (*it).a, itb = (*it).b;
//cout << "luam\n";
//cout << ita << " " << itb << ":\n";
for(int i = 1; i <= n; i ++) {
if(!f[i] && abs(v[i].a - ita) <= itb - v[i].b) {
f[i] = 1;
if(ms.find({v[i].a, v[i].b}) != ms.end()) {
//cout << "er\n";
ms.erase({v[i].a, v[i].b});
}
//cout << v[i].a << " " << v[i].b << "\n";
}
}
//cout << "\n";
}
//cout << "RASP: ";
cout << ans;
//cout << '\n';
//for(int i = 1; i <= n; i ++) {
//cout << i << ": " << f[i] << endl;
//}
return 0;
}
