#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n;
cin >> n;
vector<array<int, 2>> a(n);
for (int i = 0; i < n; ++i) {
for (int j = 0; j < 2; ++j) {
cin >> a[i][j];
}
}
sort(begin(a), end(a));
vector<int> ord(n);
vector<bool> vis(n);
iota(begin(ord), end(ord), 0);
sort(begin(ord), end(ord), [&](int x, int y) {
return a[x][1] > a[y][1];
});
int res = 0;
for (auto& i : ord) {
if (vis[i]) continue;
//~ cerr << "Now at = " << a[i][0] << " " << a[i][1] << "\n";
res += 1;
int sum = a[i][0] + a[i][1];
for (int j = i; j < n; ++j) {
if (vis[j] || sum < a[j][0] + a[j][1]) {
//~ cerr << "Ended at " << a[j][0] << "\n";
break;
}
if (j != i) vis[j] = 1;
}
sum = a[i][1] - a[i][0];
for (int j = i; j >= 0; --j) {
if (vis[j] || sum < a[j][1] - a[j][0]) {
//~ cerr << "Ended at " << a[j][0] << "\n";
break;
}
vis[j] = true;
}
}
cout << res << "\n";
}
