#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <immintrin.h>
#ifndef DEBUG
//#pragma GCC optimize("O3")
//#pragma GCC target("avx2")
#endif
using namespace __gnu_pbds;
using namespace __gnu_cxx;
using namespace std;
//
using ld = long double;
using ll = long long;
using i128 = __int128;
using ull = unsigned long long;
using pll = std::pair<ll, ll>;
using cmpl = std::complex<ld>;
template<typename T>
using oset = tree<T, null_type, std::less<T>, rb_tree_tag, tree_order_statistics_node_update>;
constexpr ll MOD1 = 998244353;
constexpr ll MOD = 1000000007;
constexpr ll INV2 = 499122177;
constexpr ld PI = 3.141592653589793;
const ld eps = 1e-7;
const ll K = 3;
//const ll C = 200;
std::mt19937 rnd(std::chrono::steady_clock::now().time_since_epoch().count());
ld START_TIME = clock();
bool cmp(pll a, pll b){
return (a.first - a.second) < (b.first - b.second) || (((a.first - a.second) == (b.first - b.second)) && ((a.first + a.second) > (b.first + b.second)));
}
void solve() {
ll n;
std::cin >> n;
std::vector<pll> a(n);
for (int i = 0; i < n; ++i) {
std::cin >> a[i].first >> a[i].second;
}
std::sort(a.begin(), a.end(), cmp);
ll ans = 0;
std::vector<ll> used(n);
std::vector<pll> bb;
ll max = -1;
for (int i = 0; i < n; ++i) {
if (a[i].second + a[i].first > max){
max = std::max(max, a[i].second + a[i].first);
++ans;
}
}
std::cout << ans;
}
signed main() {
#ifdef DEBUG
std::freopen("/home/anton/CLionProjects/untitled/input.txt", "r", stdin);
#else
// std::freopen("tri.in", "r", stdin); std::freopen("tri.out", "w", stdout);
#endif
// std::cin.tie(nullptr)->std::ios_base::sync_with_stdio(false);
int tt = 1;
// std::cin >> tt;
while (tt--) {
solve();
}
#ifdef DEBUG
std::cerr << '\n';
ld TIME = (clock() - START_TIME) / CLOCKS_PER_SEC;
std::cerr << "Time: " << TIME << '\n';
#endif
}
