#include <bits/stdc++.h>
using namespace std;
#ifdef ngu
#include "debug.h"
#else
#define debug(...) 42
#endif
signed main() {
ios::sync_with_stdio(false);
cin.tie(0);
#ifdef ngu
freopen("test.inp", "r", stdin);
freopen("test.out", "w", stdout);
#endif
int n;
cin >> n;
vector<int> x(n), e(n);
for (int i = 0; i < n; ++i) {
cin >> x[i] >> e[i];
}
auto vx = x;
auto ve = e;
sort(vx.begin(), vx.end());
vx.erase(unique(vx.begin(), vx.end()), vx.end());
sort(ve.begin(), ve.end());
ve.erase(unique(ve.begin(), ve.end()), ve.end());
for (int i = 0; i < n; ++i) {
x[i] = lower_bound(vx.begin(), vx.end(), x[i]) - vx.begin();
e[i] = lower_bound(ve.begin(), ve.end(), e[i]) - ve.begin();
}
vector<vector<int>> g((int) ve.size());
for (int i = 0; i < n; ++i) {
g[e[i]].emplace_back(i);
}
int m = (int) vx.size();
const int INF = (int) 1e9;
vector<int> sum(m, -INF), dif(m, INF);
set<int> s;
auto cover = [&](int i) {
if (!s.size()) {
return false;
}
int X = vx[x[i]];
int E = ve[e[i]];
auto it = s.lower_bound(x[i]);
if (it != s.end()) {
int r = *it;
if (dif[r] <= X - E) {
return true;
}
}
if (it != s.begin()) {
int l = *prev(it);
if (X + E <= sum[l]) {
return true;
}
}
return false;
};
auto ins = [&](int i) {
int X = vx[x[i]];
int E = ve[e[i]];
dif[x[i]] = min(dif[x[i]], X - E);
sum[x[i]] = max(sum[x[i]], X + E);
s.erase(x[i]);
if (s.size()) {
auto it = s.lower_bound(x[i]);
if (it != s.end()) {
sum[*it] = max(sum[*it], sum[x[i]]);
}
if (it != s.begin()) {
int l = *prev(it);
dif[l] = min(dif[l], dif[x[i]]);
}
}
s.insert(x[i]);
};
int res = 0;
for (int i = (int) g.size() - 1; ~i; --i) {
for (int j : g[i]) {
if (!cover(j)) {
res++;
ins(j);
}
}
}
cout << res;
}
