#include <bits/stdc++.h>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
//#define int long long
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
const int mod = 1e9 + 7;
const int LOG = 20;
const int maxn = 1e5 + 5;
signed main() {
int n;
cin >> n;
//xi - xj >= ei - ej
//xi - ei >= xj - ej
//xj - xi >= ei - ej
//xj + ej >= xi + ei
//xi + ei <= xj + ej
vector<pii> v(n);
for(int i=0; i<n; i++) {
int a, b;
cin >> a >> b;
v[i] = { a - b, a + b };
}
//vo koordinati treba x1 >= x2 i y1 <= y2 (za 1 da go izede 2)
sort(v.rbegin(), v.rend());
vector<int> dp(n, 1e9); dp[0] = 1;
for(int i=0; i<n; i++) {
for(int j=i; j<n; j++) {
if(v[j].second < v[i].second) break;
dp[j] = min(dp[j], 1 + (i ? dp[i-1] : 0));
}
}
cout << dp[n-1] << '\n';
return 0;
}
