/*
Author: Nguyen Chi Thanh - High School for the Gifted - VNU.HCM (i2528)
*/
#include <bits/stdc++.h>
using namespace std;
// #define int long long
#define ull unsigned long long
#define ld long double
#define pii pair<int, int>
#define fi first
#define se second
#define __builtin_popcount __builtin_popcountll
#define all(x) (x).begin(), (x).end()
#define BIT(x, i) (((x) >> (i)) & 1)
#define MASK(x) ((1ll << (x)))
#define debug(a, l, r) for (int _i = (l); _i <= (r); ++_i) cout << (a)[_i] << ' '; cout << '\n';
const int MAXN = 1e7 + 5;
int n;
pii points[MAXN];
void init() {
cin >> n;
for (int i = 1; i <= n; ++i) {
int x, y; cin >> x >> y;
points[i] = {x + y, x - y};
}
}
void solve() {
sort(points + 1, points + n + 1, [](pii &x, pii &y) {
if (x.fi == y.fi) return x.se > y.se;
return x.fi < y.fi;
});
vector<int> st;
for (int i = 1; i <= n; ++i) {
pii p = points[i];
while (!st.empty() && p.se <= st.back()) st.pop_back();
st.push_back(p.se);
}
cout << (int)st.size();
}
signed main() {
#ifdef NCTHANH
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
ios_base::sync_with_stdio(0);
cin.tie(nullptr); cout.tie(nullptr);
init();
solve();
return 0;
}
