#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define rep(i,a,b) for(int i=(a); i<(b); ++i)

void solve() {
    ll n;
    cin >> n;
    vector<ll> x(n), h(n);
    rep(i, 0, n){
        cin >> x[i] >> h[i];
    }

    if(n == 1){
        cout << 1 << "\n";
        return;
    }

    ll ans = 2; // first tree always falls left, last tree always falls right
    ll last_occupied = x[0]; // rightmost occupied point after processing tree 0 (fell left)

    rep(i, 1, n - 1){
        if(x[i] - h[i] > last_occupied){
            // Fall left: segment [x[i]-h[i], x[i]] doesn't overlap with last occupied
            ans++;
            last_occupied = x[i]; // rightmost point of this tree is x[i] itself
        }
        else if(x[i] + h[i] < x[i+1]){
            // Fall right: segment [x[i], x[i]+h[i]] doesn't reach next tree
            ans++;
            last_occupied = x[i] + h[i]; // rightmost occupied extends to x[i]+h[i]
        }
        else {
            // Can't fell this tree, it stays standing
            last_occupied = x[i];
        }
    }
    cout << ans << "\n";
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    solve();
    return 0;
}