#include<bits/stdc++.h> #pragma GCC optimize("Ofast") #define ll long long #define nl "\n" #define all(v) v.begin(),v.end() #define baraa ios_base::sync_with_stdio(false);cin.tie(NULL); using namespace std; struct segtree { vector<ll> tree; ll n; segtree(ll _n) { n = _n; tree = vector<ll>(4 * n, 0); } ll get(ll i, ll l, ll r, ll ql, ll qr) { if (l >= ql && qr >= r) return tree[i]; if (ql > r || qr < l) return 0; ll leftSum = get(i * 2, l, (l + r) / 2, ql, qr); ll rightSum = get(i * 2 + 1, (l + r) / 2 + 1, r, ql, qr); return max(leftSum, rightSum); } void update(ll i,ll l,ll r,ll idx, ll val) { if (l == r) { tree[i] = val; return; } if (idx <= (l + r) / 2)update(i * 2, l, (l + r) / 2, idx, val); else update(i * 2 + 1, (l + r) / 2 + 1, r, idx, val); tree[i] = max(tree[i * 2], tree[i * 2 + 1]); } ll get(ll l, ll r) { return get(1, 0, n - 1, l, r); } void update(ll idx, ll val) { update(1, 0, n - 1, idx, val); } }; int main() { baraa ll n; cin >> n; vector<ll> l(n), r(n); for (ll i = 0; i < n; i++)cin >> l[i] >> r[i]; vector<ll> dp(n + 1, 1), dp2(n + 1, 0); priority_queue<array<ll, 2> > pq; segtree seg(n); for (ll i = n - 1; i >= 0; i--) { while (pq.size() and pq.top()[0] > i) { auto [val, idx] = pq.top(); dp2[idx] = dp[idx]; seg.update(idx, dp[idx]); pq.pop(); } // for (ll j = i + r[i] + 1; j < n; j++) // dp[i] = max(dp[i], dp2[j] + 1); dp[i] = seg.get(i + r[i] + 1, n - 1) + 1; pq.push({i - l[i], i}); } cout << *max_element(all(dp)); return 0; }