#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
typedef long long ll;
typedef pair<long long, long long> pll;
typedef pair<int,int> pii;
typedef vector<long long> vl;
typedef vector<int> vi;
int n;
vector<pii> arr;
// abs(xi - xj) <= yi - yj -> we place on i
// let xi >= xj
// yj - xj <= yi - xi
// let xi < xj
// xj + yj <= yi + xi
int tree_levo[4 * 200100], tree_desno[4 * 200100];
// tree_levo - check left side
// tree_desno - check right side;
void build(int node, int l, int r){
if(l == r){
tree_levo[node] = -1e9;
tree_desno[node] = -1e9;
}
else{
int mid = (l + r) / 2;
build(node*2, l, mid);
build(node*2+1, mid+1, r);
tree_levo[node] = max(tree_levo[node*2], tree_levo[node*2+1]);
tree_desno[node] = max(tree_desno[node*2], tree_desno[node*2+1]);
}
}
void update_levo(int node, int l, int r, int pos, int set){
if(l == r) tree_levo[node] = set;
else{
int mid = (l + r) / 2;
if(pos <= mid) update_levo(node*2, l, mid, pos, set);
else update_levo(node*2+1, mid+1, r, pos, set);
tree_levo[node] = max(tree_levo[node*2], tree_levo[node*2+1]);
}
}
void update_desno(int node, int l, int r, int pos, int set){
if(l == r) tree_desno[node] = set;
else{
int mid = (l + r) / 2;
if(pos <= mid) update_desno(node*2, l, mid, pos, set);
else update_desno(node*2+1, mid+1, r, pos, set);
tree_desno[node] = max(tree_desno[node*2], tree_desno[node*2+1]);
}
}
int query_levo(int node, int l, int r, int L, int R){
if(r < L || l > R) return -1e9;
if(L <= l && r <= R) return tree_levo[node];
int mid = (l + r) / 2;
int left = query_levo(node*2, l, mid, L, R);
int right = query_levo(node*2+1, mid+1, r, L, R);
return max(left, right);
}
int query_desno(int node, int l, int r, int L, int R){
if(r < L || l > R) return -1e9;
if(L <= l && r <= R) return tree_desno[node];
int mid = (l + r) / 2;
int left = query_desno(node*2, l, mid, L, R);
int right = query_desno(node*2+1, mid+1, r, L, R);
return max(left, right);
}
//1 1 -> 0
//3 2 -> 1
//4 3 -> 2
//5 1 -> 3
// 4 3
// update_desno na pozicija 2 -> -1
// update_levo na pozicija 2 -> 7
// 3 2
// query_desno za (0, 1) ke dade -1
// query_levo za (2, 3) ke dade 7
// 5 1
// 1 1
int check(pii a, pii b){
int c = b.first - a.first;
if(a.second - b.second >= c) return 1;
if(b.second - a.second >= c) return 2;
return 0;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
cin>>n;
arr.resize(n);
priority_queue<pii> pq;
bool all = true;
for(int i = 0; i < n; i++){
cin>>arr[i].first>>arr[i].second;
if(arr[i].second > 1) all = false;
// pq.push(mp(arr[i].second, i));
}
bool jump = true;
sort(arr.begin(), arr.end());
if(all){
int ans = 0;
for(int i = 0; i < n; i++){
if(arr[i].second==1) ans++;
}
for(int i = 0; i < n; i++){
if(arr[i].second == 0){
if(i-1 >=0 && arr[i-1].second == 0 && i + 1 < n && arr[i+1].second == 0) ans++;
else if(i == 0 && arr[i+1].second == 0) ans++;
else if(i + 1== n && arr[i-1].second == 0) ans++;
else continue;
}
else
continue;
}
cout<<ans<<endl;
return 0;
}
else if(n <= 200000){
for(int i = 0; i < n; i++){
pq.push(mp(arr[i].second, i));
}
build(1, 0, n-1);
bool vis[n];
memset(vis, false, sizeof vis);
int ans = 0;
while(!pq.empty()){
pii here = pq.top();
pq.pop();
int pos = here.second;
// cout<<pos<<endl;
// cout<<query_levo(1, 0, n-1, 0, pos-1)<<" "<<arr[pos].second + arr[pos].first<<endl;
// cout<<query_desno(1, 0, n-1, pos+1, n-1)<<" "<<arr[pos].second - arr[pos].first<<endl;
if(query_levo(1, 0, n-1, 0, pos-1) >= arr[pos].second + arr[pos].first) continue;
else if(query_desno(1, 0, n-1, pos+1, n-1) >= arr[pos].second - arr[pos].first) continue;
else{
// cout<<pos<<endl;
ans++;
update_levo(1, 0, n-1, pos, arr[pos].second + arr[pos].first);
update_desno(1, 0, n-1, pos, arr[pos].second - arr[pos].first);
}
// update_levo(1, 0, n-1, pos, arr[pos].second + arr[pos].first);
// update_desno(1, 0, n-1, pos, arr[pos].second - arr[pos].first);
}
cout<<ans<<endl;
return 0;
}
else{
int ans = 0;
stack<pii> st;
for(int i = 0; i < n; i++){
if(i == 0){
st.push(arr[i]);
continue;
}
while(!st.empty()){
int x = check(st.top(), arr[i]);
if(x == 0){
st.push(arr[i]);
break;
}
if(x==1) break;
st.pop();
if(st.empty()) st.push(arr[i]);
}
}
cout<<st.size()<<endl;
return 0;
}
}
