#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define MOD 998244353
void solve(){
ll n,l , r, ans = 0;
cin >> n;
vector<pair<ll,ll>> intervals;
for(int i = 1; i <= n; i++){
cin >> l >> r;
l = max(0ll, i - l);
r = min(n, i + r);
intervals.push_back({l, r});
}
sort(intervals.begin(), intervals.end(), [&](auto a, auto b){
return a.second < b.second;
});
ll r1 = intervals[0].second;
for (int i = 1; i < intervals.size(); i++) {
ll l1 = intervals[i].first, r2 = intervals[i].second;
if (l1 > r1) {
r1 = r2;
ans++;
}
}
cout << ans + 1 << '\n';
}
int main() {
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
int tests = 1;
// cin >> tests;
for(int i = 1; i <= tests; i ++)
solve();
}
