#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <bits/stdc++.h>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ldb;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef pair<ldb,ldb> pdd;
#define ff(i,a,b) for(int i = a; i <= b; i++)
#define fb(i,b,a) for(int i = b; i >= a; i--)
#define trav(a,x) for(auto& a : x)
#define sz(a) (int)(a).size()
#define fi first
#define se second
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
// os.order_of_key(k) the number of elements in the os less than k
// *os.find_by_order(k) print the k-th smallest number in os(0-based)
const int mod = 1000000007;
const int inf = 2e9 + 5;
const int mxN = 500005;
int n;
pii niz[mxN];
int id1[mxN];
bool cmp1(int i, int j){
return niz[i].fi < niz[j].fi;
}
int id2[mxN];
bool cmp2(int i, int j){
return niz[i].se > niz[j].se;
}
int pos[mxN];
struct SegTreeMX{
int bor[4 * mxN];
void build(int v, int tl, int tr){
bor[v] = -inf;
if(tl == tr)return;
int mid = (tl + tr) / 2;
build(v * 2, tl, mid); build(v * 2 + 1, mid + 1, tr);
}
void update(int v, int tl, int tr, int pos, int val){
if(tl == tr){
bor[v] = val;
return;
}
int mid = (tl + tr) / 2;
if(pos <= mid)update(v * 2, tl, mid, pos, val);
else update(v * 2 + 1, mid + 1, tr, pos, val);
bor[v] = max(bor[v * 2], bor[v * 2 + 1]);
}
int kveri(int v, int tl, int tr, int l, int r){
if(tl > r || l > tr)return -inf;
if(tl >= l && tr <= r)return bor[v];
int mid = (tl + tr) / 2;
return max(kveri(v * 2, tl, mid, l, r), kveri(v * 2 + 1, mid + 1, tr, l, r));
}
}MX;
struct SegTreeMN{
int bor[4 * mxN];
void build(int v, int tl, int tr){
bor[v] = inf;
if(tl == tr)return;
int mid = (tl + tr) / 2;
build(v * 2, tl, mid); build(v * 2 + 1, mid + 1, tr);
}
void update(int v, int tl, int tr, int pos, int val){
if(tl == tr){
bor[v] = val;
return;
}
int mid = (tl + tr) / 2;
if(pos <= mid)update(v * 2, tl, mid, pos, val);
else update(v * 2 + 1, mid + 1, tr, pos, val);
bor[v] = min(bor[v * 2], bor[v * 2 + 1]);
}
int kveri(int v, int tl, int tr, int l, int r){
if(tl > r || l > tr)return inf;
if(tl >= l && tr <= r)return bor[v];
int mid = (tl + tr) / 2;
return min(kveri(v * 2, tl, mid, l, r), kveri(v * 2 + 1, mid + 1, tr, l, r));
}
}MN;
int main(){
cin.tie(0)->sync_with_stdio(0);
cin >> n;
ff(i,1,n)cin >> niz[i].fi >> niz[i].se;
ff(i,1,n)id1[i] = id2[i] = i;
sort(id1 + 1, id1 + n + 1, cmp1);
sort(id2 + 1, id2 + n + 1, cmp2);
ff(i,1,n)pos[id1[i]] = i;
int br = 0; MX.build(1,1,n); MN.build(1,1,n);
ff(i,1,n){
int X = niz[id2[i]].fi;
int E = niz[id2[i]].se;
int L = MX.kveri(1,1,n,1,pos[id2[i]]);
int R = MN.kveri(1,1,n,pos[id2[i]],n);
if(X + E > L && R > X - E){
br += 1;
}
MX.update(1,1,n,pos[id2[i]],X + E);
MN.update(1,1,n,pos[id2[i]],X - E);
}
cout << br << '\n';
return 0;
}
/*
4
4 2
2 3
3 4
6 5
// probati bojenje sahovski
*/
