#include <bits/stdc++.h>
using namespace std;
#define int long long
const int INF = 1e18;
const int MOD = 1e9+7;
const int MAXN = 2e5;
int n, m;
int arr[MAXN+5][5];
int dp[MAXN+5];
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
void mulaidarinol(){}
void solve(){
cin >> n;
for(int i = 1; i <= n; i++){
cin >> arr[i][0] >> arr[i][1];
arr[i][0] = min(i - 1, arr[i][0]);
arr[i][1] = min(n - i, arr[i][1]);
}
vector<pair<int, int>> v;
for(int i = 1; i <= n; i++) v.push_back({i - arr[i][0], i});
sort(v.begin(), v.end());
int mx = 0;
for(auto [kiri, idx] : v){
// cerr << "idx : " << idx << endl;
while(!pq.empty() && pq.top().first < idx){
// cerr << idx << " : " << pq.top().second << endl;
mx = max(dp[pq.top().second], mx);
pq.pop();
}
// cerr << kiri - 1 + arr[kiri-1][1] << ' ' << idx << endl;
if(kiri - 1 + arr[kiri-1][1] < idx) mx = max(dp[kiri - 1], mx);
dp[idx] = mx + 1;
if(arr[idx][1] > 0) pq.push({idx + arr[idx][1], idx});
}
int ans = 0;
for(int i = 1; i <= n; i++){
ans = max(dp[i], ans);
// cerr << "dp[" << i << "] : " << dp[i] << endl;
}
cout << ans << endl;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int tc = 1;
// cin >> tc;
while(tc--){
// mulaidarinol();
solve();
}
return 0;
}
