#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
#define pb push_back
#define pii pair<int, int>
#define pll pair<ll, ll>
#define st first
#define nd second
#define ordered_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
#define debug false
const int MAXN = 500 * 1000;
pii a[MAXN];
pii b[MAXN];
int main () {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int n;
cin >> n;
for (int i = 0; i < n; i ++) {
cin >> a[i].st >> a[i].nd;
}
for (int i = 0; i < n; i ++) {
b[i].st = a[i].nd - a[i].st;
b[i].nd = a[i].st + a[i].nd;
}
sort(b, b + n);
reverse(b, b + n);
int wyn = 0;
int maks = INT_MIN;
for (int i = 0; i < n; i ++) {
if (b[i].nd > maks) {
wyn ++;
maks = b[i].nd;
}
}
cout << wyn << "\n";
return 0;
}
