#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <math.h>
#include <cmath>
#include <set>
#include <map>
#include <cassert>
#include <algorithm>
#include <ctime>
#include <iomanip>
#include <queue>

using namespace std;

#define mp make_pair
#define sz size()
#define all(x) x.begin(),x.end()
#define forn(i,n) for (int i = 0; i<int(n); i++)
#define sqr(x) ((x)*(x))
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
const int INF = 1e9 + 7;
const ld EPS = 1e-14;
struct set_compare {
    bool operator() (const pair<ll, int> a, const pair<ll, int> b) const{
        return (a.first>b.first || a.first == b.first && a.second > b.second);
    }
};

const int NUM = 100007;
ll dp[NUM][3] = { 0 };
void init(){
    for (int i = 0; i < NUM; i++){
        for (int j = 0; j < 3; j++){
            dp[i][j] = 0;
        }
    }
}
vector<ll> xs;
vector<ll> xs1;
vector<ll> hs;
const ll INF_THIS = -1000008;
int find_ind(ll x){
    auto it = upper_bound(all(xs), x);
    if (it == xs.end())
        return -1;
    else
        return (int)(it-xs.begin());
}
int find_ind1(ll x){
    auto it = upper_bound(all(xs1), x);
    if (it == xs1.end())
        return -1;
    else
        return (int)(it - xs1.begin());
}
//#define DEBUG
int main(){
#ifdef DEBUG
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    init();
    int n;
    cin >> n;
    xs.resize(n);
    hs.resize(n);
    xs1.resize(n);
    for (int i = 0; i < xs.size(); i++){
        cin >> xs[i] >> hs[i];
        xs1[i] = xs[i] - hs[i];
        if (i>0 && xs[i] - hs[i] <= xs[i - 1])
            dp[i][1] = INF_THIS;
    }
    for (int i = 0; i < n - 1; i++){
        if (xs[i] + hs[i] >= xs[i + 1])
            dp[i][2] = INF_THIS;
    }

    for (int i = n - 1; i >= 0; i--){
        if (dp[i][0] == 0){
            if (i + 1 < n) dp[i][0] = max(dp[i + 1][0], dp[i + 1][2]);
            else
                dp[i][0] = 0;
            int ind1 = find_ind1(xs[i]);
            if (ind1 != -1 && dp[ind1][1]>=0) dp[i][0] = max(dp[i][0], dp[ind1][1]);
            dp[i][0] = max(dp[i][0], 0ll);
        }

        if (dp[i][1] == 0){
            if (i + 1 < n) dp[i][1] = max(dp[i + 1][0], dp[i + 1][2]) + 1;
            else
                dp[i][1] = 1;
            int ind1 = find_ind1(xs[i]);
            if (ind1 != -1 && dp[ind1][1]>=0) dp[i][1] = max(dp[i][1], dp[ind1][1] + 1);
            dp[i][1] = max(dp[i][1], 1ll);
        }

        if (dp[i][2] == 0){
            int ind1 = find_ind(xs[i] + hs[i]);
            if (ind1 != -1)
                dp[i][2] = max(dp[ind1][0], dp[ind1][2]) + 1;
            else
                dp[i][2] = 1;
            ind1 = find_ind1(xs[i] + hs[i]);
            if (ind1 != -1 && dp[ind1][1]>=0) dp[i][2] = max(dp[i][2], dp[ind1][1] + 1);
            dp[i][2] = max(dp[i][2], 1ll);
        }
    }

    ll ans = 0;
    ans = max(ans, dp[0][0]);
    ans = max(ans, dp[0][1]);
    ans = max(ans, dp[0][2]);
    //if (ans == 1) while (true);
    cout << ans;

#ifdef DEBUG
    cerr << "Time elapsed: " << (ld)clock() / CLOCKS_PER_SEC << " sec." << endl;
#endif
    return 0;
}