#include <bits/stdc++.h>
using namespace std;
#pragma GCC target ("avx2")
#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
#pragma GCC optimize("fast-math")
using ll = int;
#define vi vector<long long>
#define all(x) x.begin(), x.end()
#define endl "\n"
#define pr pair<ll, ll>
#define ff first
#define ss second
void solution();
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
solution();
return 0;
}
const int N = 1e7;
pr a[N];
ll avl[N+5];
inline bool isValid(int i, int j) {
return abs(a[i].ff-a[j].ff) <= a[j].ss-a[i].ss;
}
void solution() {
ll n; cin >> n;
for (int i = 0; i < n; i++) {
cin >> a[i].ff >> a[i].ss;
}
int p = -1;
for (int i = 0; i < n; i++) {
if (p == -1) avl[++p] = i;
else {
if (isValid(i, avl[p])) continue;
while (p >= 0 && isValid(avl[p], i)) p--;
avl[++p] = i;
}
}
cout << p+1 << endl;
}
