#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define vi vector<ll>
#define vvi vector<vector<ll>>
#define vs vector<string>
#define vc vector<char>
#define vb vector<bool>
#define vp vector<pair<ll, ll>>
#define pp pair<ll, ll>
#define qi queue<ll>
#define qp queue<pp>
#define pqi priority_queue<ll>
#define pqp priority_queue<pp>
#define mi map<ll, ll>
#define mpi map<pp, ll>
#define mip map<ll, pp>
#define mpp map<pp, pp>
#define mb map<ll, bool>
#define si set<ll>
#define sp set<pp>
#define mod 1000000007
#define rep(a, b) for(int a = 0; a < (b); a++)
#define inf 100000000111111111
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int n;
cin >> n;
vi X(n), E(n);
vp C(n);
rep(i, n) {
cin >> X[i] >> E[i];
C[i] = { X[i] - E[i], X[i] + E[i] };
}
sort(C.begin(), C.end());
ll MAXB = -1;
ll ans = 0;
rep(i, n) {
if (C[i].second > MAXB) {
ans++;
MAXB = C[i].second;
}
}
cout << ans << endl;
}
