#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 1e5 + 2;
const int inf = 2e9 + 2;
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int n; cin >> n;
vector<int> x(n), y(n);
for (int i = 0; i < n; i++) {
cin >> x[i] >> y[i];
}
vector<int> ord(n);
iota(ord.begin(), ord.end(), 0);
sort(ord.begin(), ord.end(), [&] (int i, int j) {
return x[i] + y[i] > x[j] + y[j];
});
int mn = inf;
int ans = 0;
for (int i : ord) if (x[i] - y[i] < mn) {
mn = x[i] - y[i];
ans += 1;
}
cout << ans << en;
return 0;
}
