#include <bits/stdc++.h>
using namespace std;
struct node {
int tl, tr, val = 0;
node *lft = nullptr, *rht = nullptr;
node (int l, int r): tl(l), tr(r) {
if (tl!=tr) {
int mid = (tl+tr)/2;
lft = new node(tl,mid);
rht = new node(mid+1, tr);
}
}
void upd(int i, int v) {
if (tl==tr) val = v;
else {
int mid = (tl+tr)/2;
if (i > mid) rht->upd(i,v);
else lft->upd(i,v);
val = max(lft->val, rht->val);
}
}
int qry(int l, int r) {
if (tl > r || tr < l) return 0;
if (tl >= l && tr <= r) return val;
return max(lft->qry(l,r), rht->qry(l,r));
}
};
signed main() {
int n;
cin >> n;
vector<int> dp(n+1,0);
vector<int> add[n+1];
node sgt(0,n);
for (int i = 1; i <= n; i++) {
int a,b;
cin >> a >> b;
dp[i] = sgt.qry(0,max(0,i-a-1)) + 1;
if (i+b <= n) add[i+b].push_back(i);
for (int j: add[i]) sgt.upd(j,dp[j]);
}
int ans = 0;
for (int i = 1; i <= n; i++) ans = max(ans, dp[i]);
cout << ans << "\n";
}
