#include <bits/stdc++.h>
#define suiii ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define ll long long
#define co cout<<
//#pragma GCC optimize("O3,Ofast,unroll-loops")
//#pragma GCC target("avx2,sse3,sse4,avx")
using namespace std;
//stuff
const ll N=exp2(ceil(log2(2e5)));
ll tre[4*N]={};
ll sumof(ll l,ll r,ll i,ll lq,ll rq){
if(l>rq||r<lq) return 0;
if(l>=lq&&r<=rq) return tre[i];
ll mid=(l+r)/2;
return sumof(l,mid,i*2,lq,rq)|sumof(mid+1,r,i*2+1,lq,rq);
}
void solve(){
ll n;
cin>>n;
ll l[n+5],r[n+5],safe[n+5]={};
set<pair<ll,ll>>s;
for(ll i=0;i<n;i++){
cin>>l[i]>>r[i];
l[i]=min(i,l[i]);
r[i]=min(n-i-1,r[i]);
s.insert({l[i]+r[i],i});
}
ll ans=0;
while(s.size()){
auto [val,idx]=*s.begin();
s.erase(s.begin());
if(sumof(0,N-1,1,idx-l[idx],idx+r[idx])==1) continue;
idx+=N;
ans++;
tre[idx]=1;
idx/=2;
while(idx){
tre[idx]=tre[idx*2]|tre[idx*2+1];
idx/=2;
}
}
co ans;
}
int main()
{
suiii
int _=1;
// cin>>_;
while(_--) solve();
return 0;
}
