#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::steady_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
const int MAXN = 5e5 + 7;
const int BASE = (1 << 19);
pll vec[MAXN];
ll tree[2 * BASE + 7][2]; // [0] z lewej, [1] z prawej
ll n;
void upd(ll k, ll ind, ll val){
ind += BASE;
tree[ind][k] = val;
ind /= 2;
while(ind > 0){
tree[ind][k] = max(tree[2 * ind][k], tree[2 * ind + 1][k]);
ind /= 2;
}
}
ll query(ll k, int v, int l, int p, ll a, ll b){
if(p < a || b < l){
return 0LL;
}
if(a <= l && p <= b){
return tree[v][k];
}
int mid = (l + p) / 2;
return max(query(k, 2 * v, l, mid, a, b), query(k, 2 * v + 1, mid + 1, p, a, b));
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n;
vector<pll> v;
for(int i = 1; i <= n; i++){
cin >> vec[i].fi >> vec[i].se;
v.pb({vec[i].se, i});
}
sort(all(v));
reverse(all(v));
ll ans = 0;
for(auto ele : v){
ll akt = ele.se;
if(vec[akt].fi - vec[akt].se > query(1, 1, 0, BASE - 1, akt, n) && vec[akt].fi + vec[akt].se > query(0, 1, 0, BASE - 1, 1, akt)){
ans++;
}
upd(1, akt, vec[akt].fi - vec[akt].se);
upd(0, akt, vec[akt].fi + vec[akt].se);
}
cout << ans << '\n';
return 0;
}
