#include <bits/stdc++.h>
//#include "includeall.h"
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
#define endl '\n'
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define lb lower_bound
#define ub upper_bound
#define input(x) scanf("%lld", &x);
#define input2(x, y) scanf("%lld%lld", &x, &y);
#define input3(x, y, z) scanf("%lld%lld%lld", &x, &y, &z);
#define input4(x, y, z, a) scanf("%lld%lld%lld%lld", &x, &y, &z, &a);
#define print(x, y) printf("%lld%c", x, y);
#define show(x) cerr << #x << " is " << x << endl;
#define show2(x,y) cerr << #x << " is " << x << " " << #y << " is " << y << endl;
#define show3(x,y,z) cerr << #x << " is " << x << " " << #y << " is " << y << " " << #z << " is " << z << endl;
#define all(x) x.begin(), x.end()
#define discretize(x) sort(x.begin(), x.end()); x.erase(unique(x.begin(), x.end()), x.end());
#define FOR(i, x, n) for (ll i =x; i<=n; ++i)
#define RFOR(i, x, n) for (ll i =x; i>=n; --i)
using namespace std;
//using namespace __gnu_pbds;
//#define ordered_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
//#define ordered_multiset tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update>
typedef long long ll;
//typedef __int128 ull;
typedef long double ld;
typedef pair<ld, ll> pd;
typedef pair<string, ll> psl;
typedef pair<ll, ll> pi;
typedef pair<pi, ll> pii;
typedef pair<pi, pi> piii;
ll const INF = 1e13;
struct node {
int s, e, m;
pi minn, maxx;
node * l, * r;
node(int S, int E) {
s = S, e = E, m = (s + e) / 2;
minn = maxx = mp(0, s);
if (s != e) {
l = new node(s, m);
r = new node(m + 1, e);
}
}
void update(int X, ll m1,ll m2) {
if (s == e) minn = mp(m1, s), maxx = mp(m2, s);
else {
if (X <= m) l -> update(X, m1, m2);
else r -> update(X, m1, m2);
minn = min(l->minn, r->minn);
maxx = max(l->maxx, r-> maxx);
}
}
pi querymin(int S, int E) {
if (S > E) return mp(INF, -1);
if (s == S && e == E) return minn;
else if (E <= m) return l -> querymin(S, E);
else if (S >= m + 1) return r -> querymin(S, E);
else return min(l -> querymin(S, m), r -> querymin(m + 1, E));
}
pi querymax(int S, int E) {
if (S > E) return mp(-INF, -1);
if (s == S && e == E) return maxx;
else if (E <= m) return l -> querymax(S, E);
else if (S >= m + 1) return r -> querymax(S, E);
else return max(l -> querymax(S, m), r -> querymax(m + 1, E));
}
}* root;
ll x[200005], e[200005];
bool die[200005];
int main()
{
ll n;
cin >> n;
root = new node(1, n);
vector<pi> v, v2(n);
for (ll i=0; i<n; ++i)
{
input2(v2[i].f, v2[i].s);
}
sort(all(v2));
for (ll i=1; i<=n; ++i)
{
x[i] = v2[i-1].f, e[i] = v2[i-1].s;
die[i] = 0;
root->update(i, x[i] + e[i], x[i] - e[i]);
v.pb(mp(e[i], i));
//show2(x[i], e[i]);
}
sort(all(v), greater<pi>());
ll ans = 0;
for (ll i=0; i<n; ++i)
{
ll idx = v[i].s;
if (die[idx]) continue;
//show(idx);
die[idx] = 1;
ans++;
root->update(idx, INF, -INF);
while (1)
{
pi cur = root->querymax(1, idx-1);
if (cur.f < x[idx] - e[idx]) break;
die[cur.s] = 1;
root->update(cur.s, INF, -INF);
}
while (1)
{
pi cur = root->querymin(idx+1, n);
if (cur.f > x[idx] + e[idx]) break;
die[cur.s] = 1;
root->update(cur.s, INF, -INF);
}
}
cout << ans << endl;
return 0;
}
