#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize("unroll-loops,no-stack-protector")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
using namespace __gnu_pbds;
using namespace std;
template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long ll;
typedef long double ld;
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
ll n;
cin >> n;
vector <pair<ll,ll>> arr(n);
for (int z=0;z<n;z++){
cin >> arr[z].first >> arr[z].second;
arr[z].first -= arr[z].second;
arr[z].second += arr[z].first;
}
stack <pair<ll,ll>> s;
for (int z=0;z<n;z++){
if (s.empty()){
s.push(arr[z]);
}
pair<ll,ll> s1 = s.top();
if (s1.first <= arr[z].first && arr[z].second <= s1.second) continue;
else{
while (arr[z].first <= s1.first && s1.second <= arr[z].second){
s.pop();
if (s.size() == 0) break;
}
s.push(arr[z]);
}
}
cout << s.size() << endl;
}
