#include <iostream>
#include <stdlib.h>
using namespace std;
int main()
{
    int n, j, i, min1=9999;
    int cricket, enccricket;
    int piz, saver=0, sum=1;

    string** matr;
    cin >> n;

    matr = new string*[2];

      for ( i = 0; i < n; i++)
        matr[i] = new string[n];

        for ( j = 0; j < n; j++)
        {
            cin >> cricket; // начало дня
            cin >> enccricket; // кол-во дней
            matr[0][j]=std::to_string(cricket+enccricket); // и то и то
            matr[1][j]=std::to_string(cricket);

        }
            i = 0;
            while(i<n-1) {
            for ( j = 0; j < n; j++)
            {
            piz = atoi((matr[1][j]).c_str())-atoi((matr[0][i]).c_str());
            if (piz >= 0){
                if (piz < min1){
                    min1=piz;
                    saver = j;
                }
            }
        }
        if (min1!=9999){
            sum+=1;
            min1=9999;
            i = saver;
        }
        else {
            i+=1;
        }
    }

    cout << sum;
    return 0;
}