#include <bits/stdc++.h>
using namespace std;
bool comp(pair <int, int> a, pair <int, int> b) {
return a.second < b.second;
}
int main() {
int n;
cin >> n;
vector <pair <int, int>> nums(n+1);
for (int i = 1; i <= n; i++) {
cin >> nums[i].first >> nums[i].second;
}
vector <int> dp(n+1);
// let dp[i] = maximum number of tulips that may be picked if the ith tulip is def picked
for (int i = 1; i <= n; i++) {
int l = i - nums[i].first;
dp[i] = 1;
for (int j = l-1; j >= 1; j--) {
int r = j + nums[j].second + 1;
if (r <= i)
dp[i] = max(dp[i], dp[j] + 1);
}
}
cout << *max_element(dp.begin(), dp.end()) << '\n';
}
