#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define l(a, b, i) for (ll i = a; i < b; i++)
#define rl(a, b, i) for (ll i = a; i >= b; i--)
#define vpair vector<pair<ll, ll>>
#define inf LLONG_MAX
#define ninf LLONG_MIN
bool cmp(const pair<ll, ll>& a, const pair<ll, ll>& b) {
if (a.first != b.first)
return a.first > b.first; // decreasing first
return a.second < b.second; // increasing second
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
ll N, X, E; cin >> N; vector<pair<ll, ll>> vec(N + 1);
l(1, N + 1, i) {
cin >> X >> E;
vec[i] = {X + E, X - E};
}
sort(vec.begin() + 1, vec.end(), cmp);
ll cnt = 1;
ll curmin = vec[1].second;
l(2, N + 1, i) {
if (vec[i].second < curmin) {
curmin = vec[i].second;
cnt++;
}
}
cout << cnt;
}
