#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <string>
#define rep(i, s, e) for (ll i = s; i < e; i++)
#define upmax(a, b) a = max(a, b)
#define upmin(a, b) a = min(a, b)
using namespace std;
using ll = int;
using vll = vector<ll>;
using vvll = vector<vll>;
using pll = pair<ll, ll>;
using vpll = vector<pll>;
inline int readInt() {
int x = 0; char ch = getchar_unlocked(); bool s = 1;
while (ch < '0' || ch>'9') { if (ch == '-')s = 0; ch = getchar_unlocked(); }
while (ch >= '0' && ch <= '9') { x = (x << 3) + (x << 1) + ch - '0'; ch = getchar_unlocked(); }
return s ? x : -x;
}
void solve() {
ll n;
n = readInt();
vpll p(n);
rep(i, 0, n) {
p[i].first = readInt();
p[i].second = readInt();
}
vpll arr(n);
rep(i, 0, n) {
arr[i].first = p[i].first - p[i].second;
arr[i].second = p[i].first + p[i].second;
}
vpll pref(n);
pref[n - 1].first = arr[n - 1].first;
pref[0].second = arr[0].second;
rep(i, 1, n) pref[i].second = max(pref[i - 1].second, arr[i].second);
for (ll i = n - 2; i >= 0; i--) pref[i].first = min(pref[i + 1].first, arr[i].first);
ll ans = n;
rep(i, 0, n) {
if ((i < n - 1 && pref[i + 1].first <= arr[i].first) || (i > 0 && pref[i - 1].second >= arr[i].second)) {
ans--;
}
}
cout << ans << '\n';
/*
vector<bool> ans(n, true);
ll mn = arr[n - 1];
for (ll i = n - 2; i >= 0; i--) {
if (arr[i] >= mn) {
ans[i] = false;
}
else mn = arr[i];
}
ll mx = arr2[0];
rep(i, 1, n) {
if (arr2[i] <= mx) {
ans[i] = false;
}
else mx = arr2[i];
}
ll res = 0;
rep(i, 0, n) if (ans[i]) res++;
cout << res << '\n';*/
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
solve();
}
