#include <bits/stdc++.h>
using namespace std;
#define int long long
using ii = pair<int, int>;
const int N = 5e5 + 5;
const long long INF = 1e16;
int n, x[N], e[N];
struct SegTree{
ii st[N << 2];
ii Merge(ii x, ii y){ return make_pair(max(x.first, y.first), min(x.second, y.second)); }
void build(int tl, int tr, int i){
if(tl == tr){
st[i] = {-INF, INF};
return;
}
int tm = tl + tr >> 1;
build(tl, tm, i<<1);
build(tm + 1, tr, i<<1|1);
st[i] = Merge(st[i<<1], st[i<<1|1]);
}
void update(int pos, ii x, int tl, int tr, int i){
if(tl == tr){
st[i] = Merge(st[i], x);
return;
}
int tm = tl + tr >> 1;
if(pos <= tm) update(pos, x, tl, tm, i<<1);
else update(pos, x, tm + 1, tr, i<<1|1);
st[i] = Merge(st[i<<1], st[i<<1|1]);
}
ii get(int l, int r, int tl, int tr, int i){
if(r < tl || tr < l || l > r) return make_pair(-INF, INF);
if(l <= tl && tr <= r) return st[i];
int tm = tl + tr >> 1;
return Merge(get(l, r, tl, tm, i<<1), get(l, r, tm + 1, tr, i<<1|1));
}
} it;
int32_t main(){
cin.tie(0)->sync_with_stdio(0);
// #define task "test"
// if(fopen(task ".inp", "r")){
// freopen(task ".inp", "r", stdin);
// freopen(task ".out", "w", stdout);
// }
cin >> n;
for(int i = 1; i <= n; i++) cin >> x[i] >> e[i];
vector<int> order(n), rrh;
iota(order.begin(), order.end(), 1);
sort(order.begin(), order.end(), [&](int i, int j){ return e[i] > e[j]; });
for(int i = 1; i <= n; i++) rrh.push_back(x[i]);
sort(rrh.begin(), rrh.end());
rrh.erase(unique(rrh.begin(), rrh.end()), rrh.end());
int res = 0, lim = rrh.size();
auto id = [&](int x)->int{
return lower_bound(rrh.begin(), rrh.end(), x) - rrh.begin() + 1;
};
it.build(1, lim, 1);
for(auto i : order){
int pos = id(x[i]);
if(it.get(1, pos, 1, lim, 1).first >= x[i] + e[i]) continue;
if(it.get(pos, lim, 1, lim, 1).second <= x[i] - e[i]) continue;
res += 1;
it.update(i, make_pair(x[i] + e[i], x[i] - e[i]), 1, lim, 1);
}
cout << res << "\n";
return 0;
}
