//EGOI 2024 Bouquet
//https://qoj.ac/contest/1764/problem/9183
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector<ll>;
struct Segtree{
vll tree; ll sz;
Segtree(ll n){
sz=1; while(sz<n) sz*=2;
tree.assign(2*sz,0);
}
void update(ll pos,ll delta,ll x,ll lx,ll rx){
if(rx-lx==1){tree[x]=delta; return;}
ll m=(lx+rx)/2;
if(pos<m) update(pos,delta,2*x+1,lx,m);
else update(pos,delta,2*x+2,m,rx);
tree[x]=max(tree[2*x+1],tree[2*x+2]);
}
void update(ll pos,ll delta){update(pos,delta,0,0,sz);}
ll query(ll l,ll r,ll x,ll lx,ll rx){
if(rx<=l || r<=lx) return 0;
if(l<=lx && rx<=r) return tree[x];
ll m=(lx+rx)/2;
return max(query(l,r,2*x+1,lx,m),query(l,r,2*x+2,m,rx));
}
ll query(ll l,ll r){return query(l,r,0,0,sz);}
};
int main(){
ll n;
cin >> n;
vll L(n+1), R(n+1); vector<pair<ll,ll>> A[n+2];
for(int i=1; i<=n; i++) cin >> L[i] >> R[i];
Segtree dp(n+1); dp.update(0,0);
for(int i=1; i<=n; i++){
for(auto [a,b]:A[i]) dp.update(a,b);
ll x=dp.query(0,max(1ll,i-L[i]))+1; A[min(n+1,i+R[i]+1)].push_back({i,x});
}
for(auto [a,b]:A[n+1]) dp.update(a,b);
cout << dp.query(0,n+1) << "\n";
}
