#include <bits/extc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
#define int long long
#define f first
#define s second
#define all(x) x.begin(), x.end()
#define debug(x) do{auto y = x; cout << #x << " = " << y << endl;}while(0)
// #define endl "\n"
#define unordered_map __gnu_pbds::gp_hash_table
using pii = pair<int, int>;
const int inf = 1ll << 60;
const int MOD = 1e9 + 7;
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int n; cin >> n;
vector<pii> pts(n);
for(int i = 0; i < n; i++) {
int x, y; cin >> x >> y;
pts[i] = {x - y, -(x + y)};
}
sort(all(pts));
int hi = -inf;
int ans = 0;
for(auto p : pts) {
p.s *= -1;
if(p.s > hi) {
hi = p.s;
ans++;
}
}
cout << ans << endl;
}
