#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
int n; cin >> n;
int X[n + 1] = {}, E[n + 1] = {};
map<int, int> ma, best;
for (int i = 1; i <= n; i++){
cin >> X[i] >> E[i];
ma[X[i]] = max(ma[X[i]], E[i]);
}
for (int i = 1; i <= n; i++){
if (ma[X[i]] == E[i]) best[X[i]] = i;
}
map<int, vector<int>> idx;
vector<int> iter;
for (int i = 1; i <= n; i++){
if (idx[E[i]].size() == 0) iter.push_back(E[i]);
idx[E[i]].push_back(i);
}
sort(iter.rbegin(), iter.rend());
vector<int> a;
for (auto i : iter){
for (auto j : idx[i]) a.push_back(j);
}
int ans = 0;
int vis[n + 1] = {};
for (auto i : a){
if (vis[i]) continue;
ans++;
vis[i] = 1;
int idx = i - 1;
while (idx > 0 && vis[idx] == 0){
if (abs(X[i] - X[idx]) <= E[i] - E[idx]){
vis[idx] = 2;
}
idx--;
}
idx = i + 1;
while (idx <= n && vis[idx] == 0){
if (abs(X[i] - X[idx]) <= E[i] - E[idx]){
vis[idx] = 2;
}
idx++;
}
}
// for (int i = 1; i <= n; i++) cout << vis[i] << ' ';
// cout << endl;
cout << ans << endl;
}
