#include<iostream>
#include<vector>
#include<set>
using namespace std;
typedef pair<int,int> pii;
vector<int> dp;
vector<int> bit;
void update(int p, int val) {
for(; p<bit.size(); p+=p&(-p))
bit[p] = max(bit[p], val);
return;
}
int query(int p) {
int res = 0;
for(; p; p-=p&(-p))
res = max(res, bit[p]);
return res;
}
int main() {
int N;
cin>>N;
dp.resize(N+1, 0);
bit.resize(N+1, 0);
set<pii> st;
vector<pii> tulips(N+1);
vector<vector<int>> bucket(N+5);
for(int i=1; i<=N; i++) {
cin>>tulips[i].first>>tulips[i].second;
}
for(int i=1; i<=N; i++) {
auto [l, r] = tulips[i];
// [0, i-l+1] find the one that is valid and with the largest dp
for(int index:bucket[i]) update(index, dp[index]);
int best = 0;
if(i-l-1>=1) best = max(best, query(i-l-1));
dp[i] = max(dp[i-1],best+1);
if(i+r+1<=N) bucket[i+r+1].push_back(i);
}
cout<<dp[N];
}
