// Hallelujah, praise the one who set me free
// Hallelujah, death has lost its grip on me
// You have broken every chain, There's salvation in your name
// Jesus Christ, my living hope
#include <bits/stdc++.h>
using namespace std;
#define REP(i, s, e) for (int i = (s); i < (e); i++)
#define RREP(i, s, e) for (int i = (s); i >= (e); i--)
template <class T>
inline bool mnto(T& a, T b) {return a > b ? a = b, 1 : 0;}
template <class T>
inline bool mxto(T& a, T b) {return a < b ? a = b, 1: 0;}
typedef long long ll;
typedef long double ld;
#define FI first
#define SE second
typedef pair<int, int> ii;
typedef pair<ll, ll> pll;
typedef tuple<int, int, int> iii;
#define ALL(_a) _a.begin(), _a.end()
#define SZ(_a) (int) _a.size()
#define pb push_back
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<ii> vii;
typedef vector<iii> viii;
#ifndef DEBUG
#define cerr if (0) cerr
#endif
const int INF = 2000000005;
const ll LINF = 1000000000000000005ll;
const int MAXN = 500005;
int n;
ii xe[MAXN];
int inv[MAXN];
vii ord;
int ans;
#define MLR int mid = lo + hi >> 1, lc = u << 1, rc = u << 1 ^ 1
int sub[MAXN * 4], add[MAXN * 4];
void upd(int p, int s, int a, int u = 1, int lo = 1, int hi = n) {
if (lo == hi) {
mxto(sub[u], s);
mxto(add[u], a);
return;
}
MLR;
if (p <= mid) {
upd(p, s, a, lc, lo, mid);
} else {
upd(p, s, a, rc, mid + 1, hi);
}
sub[u] = max(sub[lc], sub[rc]);
add[u] = max(add[lc], add[rc]);
cerr << u << ' ' << lo << ' ' << hi << ": " << sub[u] << '\n';
}
int qsub(int s, int e, int u = 1, int lo = 1, int hi = n) {
if (lo >= s && hi <= e) {
return sub[u];
}
MLR;
int mx = -INF;
if (s <= mid) {
mxto(mx, qsub(s, e, lc, lo, mid));
}
if (e > mid) {
mxto(mx, qsub(s, e, rc, mid + 1, hi));
}
return mx;
}
int qadd(int s, int e, int u = 1, int lo = 1, int hi = n) {
if (lo >= s && hi <= e) {
return add[u];
}
MLR;
int mx = -INF;
if (s <= mid) {
mxto(mx, qadd(s, e, lc, lo, mid));
}
if (e > mid) {
mxto(mx, qadd(s, e, rc, mid + 1, hi));
}
return mx;
}
int main() {
#ifndef DEBUG
ios::sync_with_stdio(0), cin.tie(0);
#endif
cin >> n;
REP (i, 0, n) {
cin >> xe[i].FI >> xe[i].SE;
}
sort(xe, xe + n);
REP (i, 0, n) {
ord.pb({xe[i].SE, i});
}
int prv = -1, ptr = 0;
REP (i, 0, n) {
if (xe[i].FI != prv) {
prv = xe[i].FI;
ptr++;
}
inv[ptr] = xe[i].FI;
xe[i].FI = ptr;
}
sort(ALL(ord), greater<ii>());
REP (i, 0, 4 * MAXN) {
add[i] = sub[i] = -INF;
}
for (auto [_, i] : ord) {
auto [x, e] = xe[i];
cerr << x << ' ' << e << ' ' << inv[x] << '\n';
cerr << " ? " << e - inv[x] << ' ' << e + inv[x] << '\n';
int sub = qsub(x, n);
cerr << ' ' << sub << '\n';
if (sub >= e - inv[x]) {
continue;
}
int add = qadd(1, x);
cerr << ' ' << add << '\n';
if (add >= e + inv[x]) {
continue;
}
cerr << " ! " << x << ' ' << e - inv[x] << ' ' << e + inv[x] << '\n';
upd(x, e - inv[x], e + inv[x]);
ans++;
}
cout << ans << '\n';
return 0;
}
