#include <bits/stdc++.h>
using namespace std;
const int N = 500'000 + 10,
MAX = 1'000'000'000;
int n;
struct Writer {
int x, e;
friend istream& operator >> (istream& is, Writer& rhs) {
return is >> rhs.x >> rhs.e;
}
} w[N];
namespace IT {
int f[N << 2];
void update(int s, int l, int r, int p, int x) {
if (p < l || p > r) return;
if (l == r) {
f[s] = x;
return;
}
int mid = (l + r) >> 1;
update(s << 1, l, mid, p, x); update(s << 1 | 1, mid + 1, r, p, x);
f[s] = min(f[s << 1], f[s << 1 | 1]);
}
int query(int s, int l, int r, int u, int v) {
if (v < l || u > r) return MAX;
if (u <= l && r <= v) return f[s];
int mid = (l + r) >> 1;
return min(query(s << 1, l, mid, u, v), query(s << 1 | 1, mid + 1, r, u, v));
}
}
struct ST {
int mi[N][19], ma[N][19], lg[N];
void buildST(const vector<int>& arr) {
for (int i = 2; i <= n; ++i) lg[i] = lg[i >> 1] + 1;
for (int i = 1; i <= n; ++i) mi[i][0] = ma[i][0] = arr[i];
for (int j = 1; j <= 18; ++j) {
for (int i = 1; i <= n - (1 << j) + 1; ++i) {
mi[i][j] = min(mi[i][j - 1], mi[i + (1 << (j - 1))][j - 1]);
ma[i][j] = max(ma[i][j - 1], ma[i + (1 << (j - 1))][j - 1]);
}
}
}
int getMin(int l, int r) {
int j = lg[r - l + 1];
return min(mi[l][j], mi[r - (1 << j) + 1][j]);
}
int getMax(int l, int r) {
int j = lg[r - l + 1];
return max(ma[l][j], ma[r - (1 << j) + 1][j]);
}
} SMALL, GREAT;
int32_t main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n;
for (int i = 1; i <= n; ++i) cin >> w[i];
sort(w + 1, w + n + 1, [](const auto& a, const auto& b) { return a.x < b.x; });
{ // build ST
vector<int> small(1), great(1);
for (int i = 1; i <= n; ++i)
small.push_back(w[i].x - w[i].e), great.push_back(w[i].x + w[i].e);
SMALL.buildST(small); GREAT.buildST(great);
}
memset(IT::f, 63, sizeof IT::f);
IT::update(1, 0, n, 0, 0);
for (int i = 1; i <= n; ++i) {
int lt = i;
{ // go left
int le = 1, ri = i;
while (le <= ri) {
int mid = (le + ri) >> 1;
if (SMALL.getMin(mid, i) >= w[i].x - w[i].e) ri = (lt = mid) - 1;
else le = mid + 1;
}
}
int rt = i;
{ // go right
int le = i, ri = n;
while (le <= ri) {
int mid = (le + ri) >> 1;
if (GREAT.getMax(i, mid) <= w[i].x + w[i].e) le = (rt = mid) + 1;
else ri = mid - 1;
}
}
int ret = IT::query(1, 0, n, lt - 1, i - 1) + 1;
IT::update(1, 0, n, rt, min(IT::query(1, 0, n, rt, rt), ret));
}
cout << IT::query(1, 0, n, n, n) << "\n";
}
