#include<bits/stdc++.h>
using namespace std;
#define int long long
#define ii pair <int, int>
#define app push_back
#define all(a) a.begin(), a.end()
#define bp __builtin_popcountll
#define ll long long
#define mp make_pair
#define f first
#define s second
#define Time (double)clock()/CLOCKS_PER_SEC
#define debug(x) std::cout << #x << ": " << x << '\n';
signed main() {
    #ifdef HOME
    freopen("input.txt", "r", stdin);
    #else
    #define endl '\n'
    ios_base::sync_with_stdio(0); cin.tie(0);
    #endif

    int n;
    cin >> n;
    vector <int> x(n), r(n);
    for (int i = 0; i < n; ++i) {
        cin >> x[i] >> r[i];
    }   

    int ans = 0;
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < n; ++j) {
            if (i == j)
                continue;

            if (x[j] - r[j] < x[i] && x[i] < x[j] + r[j]) {
                ans++;
                break;
            }
        }   
    }   
    cout << n - ans << endl;
}