// #include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <map>
#include <vector>
#include <iomanip>
#include <string>
#include <queue>
#include <set>
#include <deque>
using namespace std;
#define int long long
#define endl "\n";
const int N=2e5+5;
const int M=1e9+7;
int n , q , x , y , p[N] , cnt[N] , ind[N];
vector<vector<int>>a(N);
vector<int>pr(N);
vector<int>e;
vector<int>l(N);
vector<pair<int,int>>li(N);
void solve()
{
cin >> n;
vector<pair<int,int>>a(n);
for (int i=0;i<n;i++){
cin >> x >> y;
a[i]={max(i-x,(int)0),min(i+y,n-1)};
}
int i=1;
int j=0;
int i1=a[0].second;
int j1=a[0].first;
y=0;
int c=1;
for (int l;i<i1;i++){
if (i1>a[i].second){
i1=a[i].second;
y=i;
}
}
// cout << y << endl;
while (i<n){
i1=n;
bool f=0;
for (int l;i<i1;i++){
if (y<a[i].first and i1>a[i].second){
i1=a[i].second;
y=i;
f=1;
}
}
// cout << y << endl;
// cout << i << " " << i1 << endl;
if (f){
c++;
}
else{
break;
}
i=a[y].second+1;
}
cout << c << endl;
}
signed main()
{
ios::sync_with_stdio(0);//DO NOT USE IN INTERACTIVE
cin.tie(0), cout.tie(0);//DO NOT USE IN INTERACTIVE
cout << fixed<<setprecision(9);
int t=1;
// cin >> t;
for (int _=1;_<=t;_++){
solve();
}
}
// Fenwick Tree
// Sqrt Decomposition
// Segment Tree
