#include <bits/stdc++.h>
using namespace std;
#define int long long
using pii = pair<int, int>;
#define IO ios::sync_with_stdio(0), cin.tie(0)
#define FOR(p, a, b) for (int p = a; p <= b; p++)
void dbg() {;}
template<class T, class ...U>
void dbg(T a, U ...b) {cout << a << (sizeof...(b) ? ", " : " "); dbg(b...);}
void ent() {cout << "\n";}
/// ---- INITIAL END ----
const int INF = 1e15;
const int N = 200005;
pii a[N];
int l[N], r[N];
int from[N], dp[N];
int S[4 * N];
void update(int node, int l, int r, int id, int val) {
if (l == r) {
S[node] = val;
return;
}
int mid = (l + r) >> 1;
if (id <= mid)
update(2 * node, l, mid, id, val);
else
update(2 * node + 1, mid + 1, r, id, val);
S[node] = min(S[2 * node], S[2 * node + 1]);
}
int query(int node, int l, int r, int ql, int qr) {
if (ql <= l & r <= qr) {
return S[node];
}
int mid = (l + r) >> 1;
if (qr <= mid)
return query(2 * node, l, mid, ql, qr);
else if (mid + 1 <= ql)
return query(2 * node + 1, mid + 1, r, ql, qr);
else
return min(query(2 * node, l, mid, ql, qr), query(2 * node + 1, mid + 1, r, ql, qr));
}
signed main() {
IO;
int n;
cin >> n;
FOR (i, 1, n) cin >> a[i].first >> a[i].second;
sort(a + 1, a + n + 1);
{
/// build l[]
deque<int> dq;
for (int i = 1; i <= n; i++) {
while (! dq.empty() && a[dq.back()].first - a[dq.back()].second >= a[i].first - a[i].second)
dq.pop_back();
if (dq.empty())
l[i] = 1;
else
l[i] = dq.back() + 1;
dq.push_back(i);
}
}
{
/// build r[]
deque<int> dq;
for (int i = n; i >= 1; i--) {
while (! dq.empty() && a[dq.back()].first + a[dq.back()].second <= a[i].first + a[i].second)
dq.pop_back();
if (dq.empty())
r[i] = n;
else
r[i] = dq.back() - 1;
dq.push_back(i);
}
}
// FOR (i, 1, n) dbg(l[i]); ent();
// FOR (i, 1, n) dbg(r[i]); ent();
fill(from, from + N, n + 1);
FOR (i, 1, n) from[r[i]] = min(from[r[i]], l[i]);
fill(dp, dp + N, INF);
fill(S, S + 4 * N, INF);
dp[0] = 0;
update(1, 0, n, 0, 0);
FOR (i, 1, n) {
if (from[i] == n + 1) continue;
dp[i] = query(1, 0, n, from[i] - 1, i - 1) + 1;
update(1, 0, n, i, dp[i]);
}
cout << dp[n] << "\n";
return 0;
}
